Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt heap memory.

It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-3279 advisory.

    Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching     via an undersized superlinear cache in S_regmatch.

    The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM     node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that     product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a     pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then     indexed from the real match position and node number, so reads go past the end of the allocation, and on     failure CACHEsayNO sets a bit past it.

    A caller that matches an attacker controlled subject of this size against a pattern of this shape can     crash the process or corrupt heap memory. (CVE-2026-15534)

    Perl versions from 5.9.4 before 5.41.9 produce incorrect regular expression match results when a stale     failure flag ends the Aho-Corasick prescan early in S_find_byclass.

    The prescan walks the subject for positions where the full pattern could match, and the engine tries it     from the leftmost one recorded. A failing transition sets the failed flag, and a later successful     transition does not clear it, so the prescan reads the stale flag as a failure and stops before it can     record a candidate that starts earlier. It takes a subject where one candidate is recorded and a later     character then forces a fallback through a fail link that succeeds.

    Example:

    ABCDE =~ m/ABCF|BCDE|C/;    # matches C at offset 2, not BCDEABCDE =~ m/ABCF|BCDE|C(G)/; # no match,     BCDE missed

    An alternation like this can miss input it should match, or match it on the wrong branch, so an access or     filtering decision made from the result can be wrong. (CVE-2026-19487)

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 version of perl installed on the remote host is prior to 5.16.3-299. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2026-4026 advisory.

    Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching     via an undersized superlinear cache in S_regmatch.

    The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM     node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that     product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a     pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then     indexed from the real match position and node number, so reads go past the end of the allocation, and on     failure CACHEsayNO sets a bit past it.

    A caller that matches an attacker controlled subject of this size against a pattern of this shape can     crash the process or corrupt heap memory. (CVE-2026-15534)

    Perl versions from 5.9.4 before 5.41.9 produce incorrect regular expression match results when a stale     failure flag ends the Aho-Corasick prescan early in S_find_byclass.

    The prescan walks the subject for positions where the full pattern could match, and the engine tries it     from the leftmost one recorded. A failing transition sets the failed flag, and a later successful     transition does not clear it, so the prescan reads the stale flag as a failure and stops before it can     record a candidate that starts earlier. It takes a subject where one candidate is recorded and a later     character then forces a fallback through a fail link that succeeds.

    Example:

    ABCDE =~ m/ABCF|BCDE|C/;    # matches C at offset 2, not BCDEABCDE =~ m/ABCF|BCDE|C(G)/; # no match,     BCDE missed

    An alternation like this can miss input it should match, or match it on the wrong branch, so an access or     filtering decision made from the result can be wrong. (CVE-2026-19487)

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.

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

    Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching     via an undersized superlinear cache in S_regmatch.

    The regex engine's superlinear cache holds one bit per subject position for each participating WHILEM     node, so the bit count is the subject length plus one times the number of nodes. Nothing checks that     product for positive overflow of the signed 32-bit count: a 286331153 byte subject matched against a     pattern with 15 participating nodes stores the count as 14, leaving a two byte cache. The cache is then     indexed from the real match position and node number, so reads go past the end of the allocation, and on     failure CACHEsayNO sets a bit past it.

    A caller that matches an attacker controlled subject of this size against a pattern of this shape can     crash the process or corrupt heap memory.(CVE-2026-15534)

    Perl versions through 5.43.10 have an integer overflow in S_measure_struct leading to an out-of-bounds     heap read in pack and unpack.

    S_measure_struct adds each item's size times its repeat count to a running total with no overflow check,     so a large repeat count in a pack or unpack template wraps the signed SSize_t total negative. The @, X,     and x position codes then guard their moves with a signed length comparison that passes when the length is     negative, advancing the buffer pointer out of bounds.

    A template derived from untrusted input can read heap memory past the buffer and return it to the     caller.(CVE-2026-57432)

    Socket versions before 2.041 for Perl have an out-of-bounds heap read.

    In Socket.xs, pack_ip_mreq_source() checks the length of its source argument before the argument is read,     so the check tests the byte length carried over from the preceding multiaddr argument instead. Both     addresses occupy a 4-byte field, so a valid multiaddr lets a source of any length pass the check, and the     source is then copied into the 4-byte imr_sourceaddr field with a fixed-size copy. A source shorter than 4     bytes is not rejected, and the copy reads up to 3 bytes past the end of its buffer.

    Calling pack_ip_mreq_source() with a source value shorter than 4 bytes copies adjacent heap memory into     the returned packed structure.(CVE-2026-12087)

    Storable versions before 3.41 for Perl have a signed integer overflow when deserializing a crafted SX_HOOK     record.

    retrieve_hook_common reads a signed 32-bit item count from an SX_HOOK record and calls av_extend with that     count plus one. A count of I32_MAX wraps the addition to a negative value.

    A crafted blob passed to thaw or retrieve triggers the overflow; av_extend receives the negative count and     dies with a panic, terminating the deserialization.(CVE-2026-57433)

Tenable has extracted the preceding description block directly from the EulerOS perl 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:

  - Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching
    via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per
    subject position for each participating WHILEM node, so the bit count is the subject length plus one times
    the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a
    286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14,
    leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads
    go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an
    attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt
    heap memory. (CVE-2026-15534)

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 26.04 LTS / Pro Realtime 22.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-8736-1 advisory.

    It was discovered that Perl incorrectly handled certain large inputs during regular expression matching.
    An attacker could possibly use this issue to trigger out-of-bounds heap reads or writes, resulting in a     denial of service or arbitrary code execution. (CVE-2026-15534)

    It was discovered that Perl incorrectly handled certain regular expression containing alternative matching     branches. An attacker could

    possibly use this issue to cause incorrect regular expression matches, resulting in security restrictions     being bypassed. (CVE-2026-19487)

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.

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

  - Perl versions through 5.45.1 have out-of-bounds heap reads and writes during regular expression matching     via an undersized superlinear cache in S_regmatch. The regex engine's superlinear cache holds one bit per     subject position for each participating WHILEM node, so the bit count is the subject length plus one times     the number of nodes. Nothing checks that product for positive overflow of the signed 32-bit count: a     286331153 byte subject matched against a pattern with 15 participating nodes stores the count as 14,     leaving a two byte cache. The cache is then indexed from the real match position and node number, so reads     go past the end of the allocation, and on failure CACHEsayNO sets a bit past it. A caller that matches an     attacker controlled subject of this size against a pattern of this shape can crash the process or corrupt     heap memory. (CVE-2026-15534)

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

ID	Name	Product	Family	Type	Severity
371875	Amazon Linux 2023 : perl, perl-Attribute-Handlers, perl-AutoLoader (ALAS2023-2026-3279)	Nessus	Amazon Linux Local Security Checks	Local	medium
371767	Amazon Linux 2 : perl (ALAS-2026-4026)	Nessus	Amazon Linux Local Security Checks	Local	medium
365021	EulerOS 2.0 SP13 : perl (EulerOS-SA-2026-4172)	Nessus	Huawei Local Security Checks	Local	high
364755	EulerOS 2.0 SP13 : perl (EulerOS-SA-2026-4081)	Nessus	Huawei Local Security Checks	Local	high
459293	Echo: perl: security update to 5.40.1-6+e16	Tenable Cloud Security	Echo Local Security Checks	Local	medium
459293	Echo: perl: security update to 5.40.1-6+e16	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	medium
344619	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS / 20.04 LTS / 22.04 LTS / 26.04 LTS / Pro Realtime 22.04 LTS : Perl vulnerabilities (USN-8736-1)	Nessus	Ubuntu Local Security Checks	Local	medium
333558	Linux Distros Unpatched Vulnerability : CVE-2026-15534	Nessus	Misc.	Local	medium

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