Regexp2: Unbounded memory amplification via large `{m}` quantifier on a zero-width subexpression
CVSS score
7.5
EPSS probability
—
Risk score
0.8
Published
8 h ago
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Impact on My Inventory
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Vulnerability description
DayBreach AI Explanation
Verified against sourcesSources read
1
Source agreement
Tam uyum
Evidence confidence
%55
Short explanation
Regexp2 versions prior to 2.3.0 allow a pattern with a large {m} quantifier on a zero‑width subexpression to allocate multi‑gigabyte memory and cause the process to be OOM‑killed on empty input.
The memory amplification can lead to denial‑of‑service and compromise system stability.
What should be done?
- Upgrade Regexp2 to version 2.3.0
- Follow the official vendor advisory
- Monitor memory usage
Chain of evidence and sources
Regexp2 2.3.0 öncesi sürümler, büyük {m} kuantörlü sıfır‑genişli alt ifadelerle çok‑gigabayt bellek tahsisine ve OOM ile sürecin sonlanmasına izin verir.
Bu sorun Regexp2 2.3.0 sürümünde düzeltilmiştir; resmi yama durumu belirsiz olduğundan, kullanıcıların vendor advisory'yi takip etmeleri önerilir.
Show the technical text from the sources
Regexp2 is a feature-rich RegExp engine for Go. Prior to version 2.3.0, when regexp2 compiles and matches a pattern containing a large fixed-count quantifier applied to a zero-width subexpression — e.g. (?:){50000000} — the match engine executes the empty loop body m-1 times, pushing two integers onto the backtracking stack on every iteration. Because the parser accepts any repetition count up to math.MaxInt32 and the backtracking stack grows without bound, a pattern of fewer than 20 bytes matched against an empty input can force multi-gigabyte allocation and OOM-kill the process. MatchTimeout does not fully mitigate this because the memory is allocated faster than the 100 ms timeout clock can fire. This issue has been patched in version 2.3.0.
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE: CWE-400, CWE-770
This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-77299 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | dlclark | regexp2 | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 7.5 | CVSS V3_1 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | CVE CNA |
| 7.5 | CVSS V31 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-77299 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-77299 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
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