pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.

The remote Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8712-1 advisory.

    It was discovered that pyasn1 did not properly bound the size of long-form tag identifiers when parsing     BER, CER, or DER encoded data. An attacker could possibly use this issue to cause applications decoding     untrusted ASN.1 data to consume excessive CPU resources, resulting in a denial of service.
    (CVE-2026-59884)

    It was discovered that pyasn1 processed OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time     relative to the number of arcs. An attacker could possibly use this issue to cause applications decoding     untrusted ASN.1 data to consume excessive CPU resources, resulting in a denial of service.
    (CVE-2026-59885)

    It was discovered that pyasn1 incorrectly handled conversion of decoded REAL values to Python float types.
    An attacker could possibly use this issue to cause applications decoding untrusted ASN.1 data to consume     excessive CPU and memory resources, resulting in a denial of service. (CVE-2026-59886)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

According to the versions of the python-pyasn1 packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the univ.Real type converted its mantissa,     base, and exponent value to a Python float using exact big-integer exponentiation. A BER, CER, or DER     encoded REAL value only a few bytes long can carry a very large exponent, causing float conversion through     prettyPrint(), str(), comparison, arithmetic, int(), or an explicit float() call to consume excessive CPU     and memory and hang applications that decode untrusted ASN.1 data and then print, log, or compare decoded     objects. This issue is fixed in version 0.6.4.(CVE-2026-59886)

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER     codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID     size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing     quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any     application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version     0.6.4.(CVE-2026-59884)

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER, CER, and DER decoders process     OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs, so a small     crafted payload containing an OID with many arcs consumes excessive CPU per decode() call and can deny     service to applications that decode untrusted ASN.1 data. The corresponding encoders have the same     quadratic behavior when an application re-encodes previously decoded attacker-supplied values. This issue     is fixed in version 0.6.4.(CVE-2026-59885)

Tenable has extracted the preceding description block directly from the EulerOS python-pyasn1 security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

According to the versions of the python-pyasn1 packages installed, the EulerOS installation on the remote host is affected by the following vulnerabilities :

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the univ.Real type converted its mantissa,     base, and exponent value to a Python float using exact big-integer exponentiation. A BER, CER, or DER     encoded REAL value only a few bytes long can carry a very large exponent, causing float conversion through     prettyPrint(), str(), comparison, arithmetic, int(), or an explicit float() call to consume excessive CPU     and memory and hang applications that decode untrusted ASN.1 data and then print, log, or compare decoded     objects. This issue is fixed in version 0.6.4.(CVE-2026-59886)

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER, CER, and DER decoders process     OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs, so a small     crafted payload containing an OID with many arcs consumes excessive CPU per decode() call and can deny     service to applications that decode untrusted ASN.1 data. The corresponding encoders have the same     quadratic behavior when an application re-encodes previously decoded attacker-supplied values. This issue     is fixed in version 0.6.4.(CVE-2026-59885)

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER     codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID     size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing     quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any     application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version     0.6.4.(CVE-2026-59884)

Tenable has extracted the preceding description block directly from the EulerOS python-pyasn1 security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER
    codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID
    size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing
    quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any
    application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.
    (CVE-2026-59884)

The remote Debian 12 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4778 advisory.

    -------------------------------------------------------------------------     Debian LTS Advisory DLA-4778-1                debian-lts@lists.debian.org     https://www.debian.org/lts/security/                       Emmanuel Arias     September 09, 2026                            https://wiki.debian.org/LTS
    -------------------------------------------------------------------------

    Package        : pyasn1     Version        : 0.4.8-3+deb12u3     CVE ID         : CVE-2026-59884 CVE-2026-59885 CVE-2026-59886     Debian Bug     : 1142388

    It was discovered that pyasn1, a generic ASN.1 library for Python, is prone to     denial of service vulnerabilities, which may result in excessive CPU and memory     consumption

    CVE-2026-59884

        BER/CER/DER decoder denial of service via unbounded long-form tag IDs. The         BER decoder accumulated tag continuation octets without an upper bound, so a         crafted substrate could force construction of an arbitrarily large integer         with quadratic CPU cost.

    CVE-2026-59885

        fix quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID decoding and         encoding, which allowed denial of service via a small payload with many         arcs.

    CVE-2026-59886

        uncontrolled resource consumption when converting decoded real values.
        univ.Real convertedts mantissa, base, exponens to a Python float using exact         big-integer exponentiation, so a real value only a few bytes long could         carry a very large exponent.

    For Debian 12 bookworm, these problems have been fixed in version     0.4.8-3+deb12u3.

    We recommend that you upgrade your pyasn1 packages.

    For the detailed security status of pyasn1 please refer to     its security tracker page at:
    https://security-tracker.debian.org/tracker/pyasn1

    Further information about Debian LTS security advisories, how to apply     these updates to your system and frequently asked questions can be     found at: https://wiki.debian.org/LTS     Attachment:
    signature.asc     Description: PGP signature

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

An update of the python3 package has been released.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-3836 advisory.

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER     codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID     size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing     quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any     application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.
    (CVE-2026-59884)

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER, CER, and DER decoders process     OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs, so a small     crafted payload containing an OID with many arcs consumes excessive CPU per decode() call and can deny     service to applications that decode untrusted ASN.1 data. The corresponding encoders have the same     quadratic behavior when an application re-encodes previously decoded attacker-supplied values. This issue     is fixed in version 0.6.4. (CVE-2026-59885)

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the univ.Real type converted its mantissa,     base, and exponent value to a Python float using exact big-integer exponentiation. A BER, CER, or DER     encoded REAL value only a few bytes long can carry a very large exponent, causing float conversion through     prettyPrint(), str(), comparison, arithmetic, int(), or an explicit float() call to consume excessive CPU     and memory and hang applications that decode untrusted ASN.1 data and then print, log, or compare decoded     objects. This issue is fixed in version 0.6.4. (CVE-2026-59886)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-2000 advisory.

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER     codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID     size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing     quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any     application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.
    (CVE-2026-59884)

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER, CER, and DER decoders process     OBJECT IDENTIFIER and RELATIVE-OID values in quadratic time relative to the number of arcs, so a small     crafted payload containing an OID with many arcs consumes excessive CPU per decode() call and can deny     service to applications that decode untrusted ASN.1 data. The corresponding encoders have the same     quadratic behavior when an application re-encodes previously decoded attacker-supplied values. This issue     is fixed in version 0.6.4. (CVE-2026-59885)

    pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the univ.Real type converted its mantissa,     base, and exponent value to a Python float using exact big-integer exponentiation. A BER, CER, or DER     encoded REAL value only a few bytes long can carry a very large exponent, causing float conversion through     prettyPrint(), str(), comparison, arithmetic, int(), or an explicit float() call to consume excessive CPU     and memory and hang applications that decode untrusted ASN.1 data and then print, log, or compare decoded     objects. This issue is fixed in version 0.6.4. (CVE-2026-59886)

Tenable has extracted the preceding description block directly from the tested product security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote SUSE Linux SLED15 / SLED_SAP15 / SLES15 / SLES_SAP15 host has a package installed that is affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:3238-1 advisory.

    - CVE-2026-59884: BER/CER/DER decoder denial of service via unbounded long-form tag IDs (bsc#1271464).
    - CVE-2026-59885: quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID processing allows denial of     service       (bsc#1271465).
    - CVE-2026-59886: uncontrolled resource consumption when converting decoded REAL values (bsc#1271466).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote openSUSE 16 host has a package installed that is affected by multiple vulnerabilities as referenced in the openSUSE-SU-2026:21392-1 advisory.

    - CVE-2026-59884: BER/CER/DER decoder denial of service via unbounded long-form tag IDs (bsc#1271464).
    - CVE-2026-59885: quadratic complexity in OBJECT IDENTIFIER and RELATIVE-OID processing allows denial of     service       (bsc#1271465).
    - CVE-2026-59886: uncontrolled resource consumption when converting decoded REAL values (bsc#1271466).

Tenable has extracted the preceding description block directly from the SUSE security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - pyasn1 is a generic ASN.1 library for Python. Prior to 0.6.4, the BER decoder shared by the CER and DER     codecs parses long-form tags by accumulating continuation octets without an upper bound on the tag ID     size, allowing a crafted input to force construction of an arbitrarily large integer with CPU cost growing     quadratically and to trigger unhandled ValueError exceptions in Python 3.11+ error formatting paths. Any     application decoding untrusted BER, CER, or DER input is affected. This issue is fixed in version 0.6.4.
    (CVE-2026-59884)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
365396	Ubuntu 22.04 LTS / 24.04 LTS / 26.04 LTS : pyasn1 vulnerabilities (USN-8712-1)	Nessus	Ubuntu Local Security Checks	Local	high
365034	EulerOS 2.0 SP11 : python-pyasn1 (EulerOS-SA-2026-4369)	Nessus	Huawei Local Security Checks	Local	high
364998	EulerOS 2.0 SP11 : python-pyasn1 (EulerOS-SA-2026-4279)	Nessus	Huawei Local Security Checks	Local	high
364943	EulerOS 2.0 SP13 : python-pyasn1 (EulerOS-SA-2026-4188)	Nessus	Huawei Local Security Checks	Local	high
364829	EulerOS 2.0 SP13 : python-pyasn1 (EulerOS-SA-2026-4097)	Nessus	Huawei Local Security Checks	Local	high
460507	Echo: pyasn1: security update to 0.6.1-1+deb13u2+e3	Tenable Cloud Security	Echo Local Security Checks	Local	high
460507	Echo: pyasn1: security update to 0.6.1-1+deb13u2+e3	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
344388	Debian dla-4778 : python-pyasn1-doc - security update	Nessus	Debian Local Security Checks	Local	high
333264	Photon OS 5.0: Python3 PHSA-2026-5.0-92-0945	Nessus	PhotonOS Local Security Checks	Local	high
332047	Amazon Linux 2 : python-pyasn1, --advisory ALAS2-2026-3836 (ALAS-2026-3836)	Nessus	Amazon Linux Local Security Checks	Local	high
332035	Amazon Linux 2023 : python3-pyasn1, python3-pyasn1-modules (ALAS2023-2026-2000)	Nessus	Amazon Linux Local Security Checks	Local	high
330310	SUSE SLED15 / SLES15 Security Update : python-pyasn1 (SUSE-SU-2026:3238-1)	Nessus	SuSE Local Security Checks	Local	high
329306	openSUSE 16 Security Update : python-pyasn1 (openSUSE-SU-2026:21392-1)	Nessus	SuSE Local Security Checks	Local	high
445100	SCA: security update for pyasn1 (GHSA-m4p7-r5rc-7g4j)	Tenable Cloud Security	SCA Checks	Local	high
445100	SCA: security update for pyasn1 (GHSA-m4p7-r5rc-7g4j)	Tenable Self-Hosted Container Security	SCA Checks	Local	high
327213	Linux Distros Unpatched Vulnerability : CVE-2026-59884	Nessus	Misc.	Local	high

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