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
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.
- Published
- May 25, 2026
- Updated
- Sep 8, 2026
- EPSS
- 0.5% · 39th percentile
- CWE
- CWE-680
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Report tools
Action score
39
Monitor
Low priority for now.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.5%
CISA SSVC decision
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| perl | perl | cpe:2.3:a:perl:perl |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- perl perlup to 5.43.10 inclusive
Versions reported by the vendor
Affected version ranges reported by the assigning authority (CPANSec). Independent of NVD's CPE analysis and usually ahead of it.
cpan.org/modules perl
- before 5.40.5-RC1affected
- 5.41.0 and later · before 5.42.3-RC1affected
- 5.43.0 and later · before 5.43.11affected
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | perl | all versions | — |
| Debian:13 | perl | before 5.40.1-6+deb13u1 | 5.40.1-6+deb13u1 |
| Debian:14 | perl | before 5.40.1-8 | 5.40.1-8 |
| openSUSE:Leap 16.0 | perl | before 5.42.0-160000.3.1 | 5.42.0-160000.3.1 |
| SUSE:Linux Enterprise Micro 5.3 | perl | before 5.26.1-150300.17.23.1 | 5.26.1-150300.17.23.1 |
| SUSE:Linux Enterprise Server 12 SP5-LTSS | perl | before 5.18.2-12.35.1 | 5.18.2-12.35.1 |
| SUSE:Linux Enterprise Server 16.0 | perl | before 5.42.0-160000.3.1 | 5.42.0-160000.3.1 |
| SUSE:Linux Micro 6.0 | perl | before 5.38.2-5.1 | 5.38.2-5.1 |
| SUSE:Linux Micro 6.1 | perl | before 5.38.2-slfo.1.1_3.1 | 5.38.2-slfo.1.1_3.1 |
Same product
perl: all recordsOther highest-scoring records for the same primary product.
- CVE-2012-6329The _compile function in Maketext.pm in the Locale::Maketext implementation in Perl before 5.17.7 does not properly handle backslashes and f49Plan
- CVE-2018-18311Perl before 5.26.3 and 5.28.x before 5.28.1 has a buffer overflow via a crafted regular expression that triggers invalid write operations.43Plan
- CVE-2018-18312Perl before 5.26.3 and 5.28.0 before 5.28.1 has a buffer overflow via a crafted regular expression that triggers invalid write operations.43Plan
- CVE-2018-6913Heap-based buffer overflow in the pack function in Perl before 5.26.2 allows context-dependent attackers to execute arbitrary code via a lar42Plan
- CVE-2018-18314Perl before 5.26.3 has a buffer overflow via a crafted regular expression that triggers invalid write operations.41Plan
- CVE-2018-6797An issue was discovered in Perl 5.18 through 5.26.41Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| debian:perl | 5.40.1-6+deb13u1 · Debian:13 | Package registry (OSV) |
| opensuse:perl | 5.42.0-160000.3.1 · openSUSE:Leap 16.0 | Package registry (OSV) |
| suse:perl | 5.42.0-160000.3.1 · SUSE:Linux Enterprise Server 16.0 | Package registry (OSV) |
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-680 · Integer Overflow to Buffer OverflowCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Overflow BuffersCAPEC-100likelihood: High · Very High
- Client-side Injection-induced Buffer OverflowCAPEC-14likelihood: Medium · High
- Filter Failure through Buffer OverflowCAPEC-24likelihood: High · High
- Buffer Overflow via Symbolic LinksCAPEC-45likelihood: High · High
- Overflow Variables and TagsCAPEC-46likelihood: High · High
- Buffer Overflow via Parameter ExpansionCAPEC-47likelihood: Medium · High
- String Format Overflow in syslog()CAPEC-67likelihood: High · Very High
ATT&CK techniques
—
Change log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- github.com/Perl/perl5/commit/5e7f119eb2bb1181be908701f22bf7068e722f1c.patch
- www.openwall.com/lists/oss-security/2026/05/26/1
Vendor advisories and official records. Exploit/PoC links are deliberately left out.