Detections
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Amazon Linux 2023 : perl, perl-Attribute-Handlers, perl-AutoLoader (ALAS2023-2026-3279)
medium Nessus Plugin ID 371875
Synopsis
The remote Amazon Linux 2023 host is missing a security update.Description
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.
Solution
Run 'dnf update perl --releasever 2023.12.20261026' or or 'dnf update --advisory ALAS2023-2026-3279 --releasever 2023.12.20261026' to update your system.See Also
https://alas.aws.amazon.com//AL2023/ALAS2023-2026-3279.html
https://alas.aws.amazon.com/faqs.html
Plugin Details
Severity: Medium
ID: 371875
File Name: al2023_ALAS2023-2026-3279.nasl
Version: 1.1
Type: Local
Agent: unix
Published: 10/25/2026
Updated: 10/25/2026
Supported Sensors: Agentless Assessment, Continuous Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 5.5
Percentile: 95.72
CVSS v2
Risk Factor: Medium
Base Score: 4.7
Temporal Score: 3.5
Vector: CVSS2#AV:L/AC:H/Au:N/C:N/I:P/A:C
CVSS Score Source: CVE-2026-15534
CVSS v3
Risk Factor: Medium
Base Score: 5.7
Temporal Score: 5
Vector: CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
CPE: cpe:/o:amazon:linux:2023, p-cpe:/a:amazon:linux:perl-attribute-handlers, p-cpe:/a:amazon:linux:perl-autoloader, p-cpe:/a:amazon:linux:perl-autosplit, p-cpe:/a:amazon:linux:perl-autouse, p-cpe:/a:amazon:linux:perl-b-debuginfo, p-cpe:/a:amazon:linux:perl-b, p-cpe:/a:amazon:linux:perl-base, p-cpe:/a:amazon:linux:perl-benchmark, p-cpe:/a:amazon:linux:perl-blib, p-cpe:/a:amazon:linux:perl-class-struct, p-cpe:/a:amazon:linux:perl-config-extensions, p-cpe:/a:amazon:linux:perl-dbm_filter, p-cpe:/a:amazon:linux:perl-debugger, p-cpe:/a:amazon:linux:perl-debuginfo, p-cpe:/a:amazon:linux:perl-debugsource, p-cpe:/a:amazon:linux:perl-deprecate, p-cpe:/a:amazon:linux:perl-devel-peek-debuginfo, p-cpe:/a:amazon:linux:perl-devel-peek, p-cpe:/a:amazon:linux:perl-devel-selfstubber, p-cpe:/a:amazon:linux:perl-devel, p-cpe:/a:amazon:linux:perl-diagnostics, p-cpe:/a:amazon:linux:perl-dirhandle, p-cpe:/a:amazon:linux:perl-doc, p-cpe:/a:amazon:linux:perl-dumpvalue, p-cpe:/a:amazon:linux:perl-dynaloader, p-cpe:/a:amazon:linux:perl-encoding-warnings, p-cpe:/a:amazon:linux:perl-english, p-cpe:/a:amazon:linux:perl-errno, p-cpe:/a:amazon:linux:perl-extutils-constant, p-cpe:/a:amazon:linux:perl-extutils-embed, p-cpe:/a:amazon:linux:perl-extutils-miniperl, p-cpe:/a:amazon:linux:perl-fcntl-debuginfo, p-cpe:/a:amazon:linux:perl-fcntl, p-cpe:/a:amazon:linux:perl-fields, p-cpe:/a:amazon:linux:perl-file-basename, p-cpe:/a:amazon:linux:perl-file-compare, p-cpe:/a:amazon:linux:perl-file-copy, p-cpe:/a:amazon:linux:perl-file-dosglob-debuginfo, p-cpe:/a:amazon:linux:perl-file-dosglob, p-cpe:/a:amazon:linux:perl-file-find, p-cpe:/a:amazon:linux:perl-file-stat, p-cpe:/a:amazon:linux:perl-filecache, p-cpe:/a:amazon:linux:perl-filehandle, p-cpe:/a:amazon:linux:perl-filetest, p-cpe:/a:amazon:linux:perl-findbin, p-cpe:/a:amazon:linux:perl-gdbm_file-debuginfo, p-cpe:/a:amazon:linux:perl-gdbm_file, p-cpe:/a:amazon:linux:perl-getopt-std, p-cpe:/a:amazon:linux:perl-hash-util-debuginfo, p-cpe:/a:amazon:linux:perl-hash-util-fieldhash-debuginfo, p-cpe:/a:amazon:linux:perl-hash-util-fieldhash, p-cpe:/a:amazon:linux:perl-hash-util, p-cpe:/a:amazon:linux:perl-i18n-collate, p-cpe:/a:amazon:linux:perl-i18n-langinfo-debuginfo, p-cpe:/a:amazon:linux:perl-i18n-langinfo, p-cpe:/a:amazon:linux:perl-i18n-langtags, p-cpe:/a:amazon:linux:perl-if, p-cpe:/a:amazon:linux:perl-interpreter-debuginfo, p-cpe:/a:amazon:linux:perl-interpreter, p-cpe:/a:amazon:linux:perl-io-debuginfo, p-cpe:/a:amazon:linux:perl-io, p-cpe:/a:amazon:linux:perl-ipc-open3, p-cpe:/a:amazon:linux:perl-less, p-cpe:/a:amazon:linux:perl-lib, p-cpe:/a:amazon:linux:perl-libnetcfg, p-cpe:/a:amazon:linux:perl-libs-debuginfo, p-cpe:/a:amazon:linux:perl-libs, p-cpe:/a:amazon:linux:perl-locale-maketext-simple, p-cpe:/a:amazon:linux:perl-locale, p-cpe:/a:amazon:linux:perl-macros, p-cpe:/a:amazon:linux:perl-math-complex, p-cpe:/a:amazon:linux:perl-memoize, p-cpe:/a:amazon:linux:perl-meta-notation, p-cpe:/a:amazon:linux:perl-module-loaded, p-cpe:/a:amazon:linux:perl-mro-debuginfo, p-cpe:/a:amazon:linux:perl-mro, p-cpe:/a:amazon:linux:perl-ndbm_file-debuginfo, p-cpe:/a:amazon:linux:perl-ndbm_file, p-cpe:/a:amazon:linux:perl-net, p-cpe:/a:amazon:linux:perl-next, p-cpe:/a:amazon:linux:perl-odbm_file-debuginfo, p-cpe:/a:amazon:linux:perl-odbm_file, p-cpe:/a:amazon:linux:perl-opcode-debuginfo, p-cpe:/a:amazon:linux:perl-opcode, p-cpe:/a:amazon:linux:perl-open, p-cpe:/a:amazon:linux:perl-overload, p-cpe:/a:amazon:linux:perl-overloading, p-cpe:/a:amazon:linux:perl-ph, p-cpe:/a:amazon:linux:perl-pod-functions, p-cpe:/a:amazon:linux:perl-pod-html, p-cpe:/a:amazon:linux:perl-posix-debuginfo, p-cpe:/a:amazon:linux:perl-posix, p-cpe:/a:amazon:linux:perl-safe, p-cpe:/a:amazon:linux:perl-search-dict, p-cpe:/a:amazon:linux:perl-selectsaver, p-cpe:/a:amazon:linux:perl-selfloader, p-cpe:/a:amazon:linux:perl-sigtrap, p-cpe:/a:amazon:linux:perl-sort, p-cpe:/a:amazon:linux:perl-subs, p-cpe:/a:amazon:linux:perl-symbol, p-cpe:/a:amazon:linux:perl-sys-hostname-debuginfo, p-cpe:/a:amazon:linux:perl-sys-hostname, p-cpe:/a:amazon:linux:perl-term-complete, p-cpe:/a:amazon:linux:perl-term-readline, p-cpe:/a:amazon:linux:perl-test, p-cpe:/a:amazon:linux:perl-tests, p-cpe:/a:amazon:linux:perl-text-abbrev, p-cpe:/a:amazon:linux:perl-thread-semaphore, p-cpe:/a:amazon:linux:perl-thread, p-cpe:/a:amazon:linux:perl-tie-file, p-cpe:/a:amazon:linux:perl-tie-memoize, p-cpe:/a:amazon:linux:perl-tie, p-cpe:/a:amazon:linux:perl-time-piece-debuginfo, p-cpe:/a:amazon:linux:perl-time-piece, p-cpe:/a:amazon:linux:perl-time, p-cpe:/a:amazon:linux:perl-unicode-ucd, p-cpe:/a:amazon:linux:perl-user-pwent, p-cpe:/a:amazon:linux:perl-utils, p-cpe:/a:amazon:linux:perl-vars, p-cpe:/a:amazon:linux:perl-vmsish, p-cpe:/a:amazon:linux:perl
Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list
Exploit Ease: No known exploits are available
Patch Publication Date: 10/24/2026
Vulnerability Publication Date: 8/9/2026
Reference Information
CVE: CVE-2026-15534, CVE-2026-19487
IAVA: 2026-A-0889