VulnerabilityPublished 25 May 2026Updated 8 Sep 2026

CVE-2026-8376: perl (Perl module) · Integer Overflow to Buffer Overflow

Affects perl (Perl module)Source CVE Database V5

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Not known to be exploited · CVSS 7.3 High · fixed in 5.43.11 : patch perl (Perl module) soon.

Data as of 29 Oct 2026, 19:04 UTC

CVSS 3.1 base score

7.3High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 41% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 5.43.11, 5.42.3-RC1, 5.40.5-RC1

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact on the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade perl (Perl module) to 5.43.11, 5.42.3-RC1 or 5.40.5-RC1.

Affected software

Product	Affected	Fixed in
CPANperl`pkg:cpan/perl`Other threats	Affected <5.40.5-RC1 >=5.41.0 <5.42.3-RC1 >=5.43.0 <5.43.11	Fixed in 5.40.5-RC1 5.42.3-RC1 5.43.11

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, users should exercise caution when processing untrusted regular expressions with repeated fixed strings on 32-bit Perl builds up to version 5.43.10.

Description

Perl versions before 5.40.5-RC1, from 5.41.0 before 5.42.3-RC1, from 5.43.0 before 5.43.11 have a heap buffer overflow when compiling regular expressions with a repeated fixed string on 32-bit builds. Perl_study_chunk in regcomp_study.c checked the size of the joined substring buffer in characters rather than bytes. For a quantified fixed substring with a large minimum count, the byte length mincount * l could overflow SSize_t, producing an undersized SvGROW allocation; the subsequent copy writes past the end of the buffer. A caller that compiles an attacker-controlled regular expression on a 32-bit perl build triggers a heap buffer overflow at compile time.

Impact

Successful exploitation can lead to memory corruption on affected 32-bit Perl builds, potentially causing denial of service or other impacts related to corrupted memory. The vulnerability affects confidentiality, integrity, and availability as indicated by the CVSS vector (C:L/I:L/A:L). However, no active exploitation has been observed.

Summary

This vulnerability in Perl (CVE-2026-8376) involves an integer overflow during the calculation of buffer size when compiling regular expressions containing repeated fixed strings on 32-bit builds up to version 5.43.10. The integer overflow leads to allocation of an undersized heap buffer, which is then overflowed by out-of-bounds writes, causing memory corruption. The issue is classified under CWE-680 (Integer Overflow to Buffer Overflow). The CVSS 3.1 base score is 7.3, indicating high severity. There is no confirmed patch or official remediation available at this time, and no known exploits have been reported in the wild.

CWE-680Integer Overflow to Buffer Overflow (opens in a new tab)
Compound weakness
The product performs a calculation to determine how much memory to allocate, but an integer overflow can occur that causes less memory to be allocated than expected, leading to a buffer overflow.
MITRE discourages mapping vulnerabilities to this broad entry; the root cause is usually a more specific weakness.
OWASP Cheat Sheets
XML Security (opens in a new tab)
Mass Assignment (opens in a new tab)
OWASP ASVS 4.0.3
V5.4.3 (opens in a new tab)
V13.3.1 (opens in a new tab)
V5.1.4 (opens in a new tab)
Attack patterns
Buffer Overflow via Environment Variables (opens in a new tab)
Overflow Buffers (opens in a new tab)
Client-side Injection-induced Buffer Overflow (opens in a new tab)
Filter Failure through Buffer Overflow (opens in a new tab)
Buffer Overflow via Symbolic Links (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 29 Jun 2026, 22:48 UTC

WeaknessesCWE-680

Technical details

References

Community reviews

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