An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read. The attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len < 2, triggering the underflow when the KDC or kadmind reads principal data.

It is, therefore, affected by a vulnerability as referenced in the ALAS2-2026-3798 advisory.

    An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in     plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2)     without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then     truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and     memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.The attack     vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len     < 2, triggering the underflow when the KDC or kadmind reads principal data. (CVE-2026-11850)

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

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

It is, therefore, affected by a vulnerability as referenced in the ALAS2023-2026-1939 advisory.

    An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in     plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2)     without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then     truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and     memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.The attack     vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len     < 2, triggering the underflow when the KDC or kadmind reads principal data. (CVE-2026-11850)

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

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

The remote SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:2954-1 advisory.

    This update for krb5 fixes the following issue

    - CVE-2026-11850: integer underflow in berval2tl_data() leads to heap out-of-bounds read (bsc#1268131).

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

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

The remote SUSE Linux SLES12 host has packages installed that are affected by a vulnerability as referenced in the SUSE- SU-2026:2849-1 advisory.

    This update for krb5 fixes the following issue

    - CVE-2026-11850: integer underflow in berval2tl_data() leads to heap out-of-bounds read (bsc#1268131).

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

Note that Nessus has not tested for this issue 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 packages installed that are affected by multiple vulnerabilities as referenced in the SUSE-SU-2026:2848-1 advisory.

    This update for krb5, krb5-mini fixes the following issues

    - CVE-2026-11850: integer underflow in berval2tl_data() leads to heap out-of-bounds read (bsc#1268131).
    - CVE-2026-40355: Denial of Service via NULL pointer dereference in NegoEx mechanism (bsc#1263366).
    - CVE-2026-40356: Denial of Service via integer underflow and out-of-bounds read (bsc#1263367).

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 SUSE Linux SLES15 / SLES_SAP15 host has packages installed that are affected by a vulnerability as referenced in the SUSE-SU-2026:2847-1 advisory.

    This update for krb5 fixes the following issue

    - CVE-2026-11850: integer underflow in berval2tl_data() leads to heap out-of-bounds read (bsc#1268131).

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

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

The remote openSUSE 16 host has packages installed that are affected by a vulnerability as referenced in the openSUSE- SU-2026:21238-1 advisory.

    This update for krb5 fixes the following issue

    - CVE-2026-11850: integer underflow in berval2tl_data() leads to heap out-of-bounds read (bsc#1268131).

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

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

An update of the krb5 package has been released.

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

  - An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in     plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2)     without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then     truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and     memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read. The attack     vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len     < 2, triggering the underflow when the KDC or kadmind reads principal data. (CVE-2026-11850)

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

ID	Name	Product	Family	Severity
328841	Amazon Linux 2 : krb5, --advisory ALAS2-2026-3798 (ALAS-2026-3798)	Nessus	Amazon Linux Local Security Checks	medium
328510	Amazon Linux 2023 : krb5-devel, krb5-libs, krb5-pkinit (ALAS2023-2026-1939)	Nessus	Amazon Linux Local Security Checks	medium
326948	SUSE SLES15: krb5 / krb5-32bit / krb5-client / krb5-devel / krb5-plugin-kdb-ldap / etc (SUSE-SU-2026:2954-1)	Nessus	SuSE Local Security Checks	medium
326423	SUSE SLES12: krb5 / krb5-32bit / krb5-client / krb5-devel / krb5-doc / etc (SUSE-SU-2026:2849-1)	Nessus	SuSE Local Security Checks	medium
326422	SUSE SLED15: krb5 / krb5-32bit / krb5-client / krb5-devel / krb5-plugin-kdb-ldap / etc (SUSE-SU-2026:2848-1)	Nessus	SuSE Local Security Checks	high
326421	SUSE SLES15: krb5 / krb5-32bit / krb5-client / krb5-devel / krb5-plugin-kdb-ldap / etc (SUSE-SU-2026:2847-1)	Nessus	SuSE Local Security Checks	medium
326026	openSUSE 16: krb5 / krb5-client / krb5-devel / krb5-plugin-kdb-ldap / etc (openSUSE-SU-2026:21238-1)	Nessus	SuSE Local Security Checks	medium
324559	Photon OS 5.0: Krb5 PHSA-2026-5.0-0908	Nessus	PhotonOS Local Security Checks	medium
321101	Linux Distros Unpatched Vulnerability : CVE-2026-11850	Nessus	Misc.	medium

Detections

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CVE-2026-11850

medium

Tenable Plugins

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high

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