CVE-2024-13939
CVE-2024-13939 is a high-severity vulnerability in Fractal String with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-203.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- EPSS exploit prediction: 0% (27th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-8542
- Weakness: CWE-203
- Affected product: Fractal String
- Published:
- Last modified:
Description
String::Compare::ConstantTime for Perl through 0.321 is vulnerable to timing attacks that allow an attacker to guess the length of a secret string. As stated in the documentation: "If the lengths of the strings are different, because equals returns false right away the size of the secret string may be leaked (but not its contents)." This is similar to CVE-2020-36829
Frequently asked questions
- What is CVE-2024-13939?
- String::Compare::ConstantTime for Perl through 0.321 is vulnerable to timing attacks that allow an attacker to guess the length of a secret string. As stated in the documentation: "If the lengths of the strings are different, because equals returns false right away the size of the secret string may be leaked (but not its contents)." This is similar to CVE-2020-36829
- How severe is CVE-2024-13939?
- CVE-2024-13939 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
- Is CVE-2024-13939 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (27th percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2024-13939?
- CVE-2024-13939 affects Fractal String. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2024-13939?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2024-13939 have an EU (EUVD) identifier?
- Yes. CVE-2024-13939 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-8542.
- When was CVE-2024-13939 published?
- CVE-2024-13939 was published on 2025-03-28 and last updated on 2026-06-17.
References
Affected products (1)
- cpe:2.3:a:fractal:string\:\:compare\:\:constanttime:*:*:*:*:*:perl:*:*
Other CWE-203 (Observable Discrepancy) vulnerabilities
- CVE-2019-25337 — Critical (CVSS 9.8): OwnCloud 8.1.8 contains a username enumeration vulnerability that allows remote attackers to discover user accounts by…
- CVE-2026-23519 — Critical (CVSS 9.8): RustCrypto CMOV provides conditional move CPU intrinsics which are guaranteed on major platforms to execute in…
- CVE-2025-27667 — Critical (CVSS 9.8): Vasion Print (formerly PrinterLogic) before Virtual Appliance Host 22.0.843 Application 20.0.1923 allows Administrative…
- CVE-2024-25714 — Critical (CVSS 9.8): In Rhonabwy through 1.1.13, HMAC signature verification uses a strcmp function that is vulnerable to side-channel…
- CVE-2024-25191 — Critical (CVSS 9.8): php-jwt 1.0.0 uses strcmp (which is not constant time) to verify authentication, which makes it easier to bypass…
- CVE-2024-25190 — Critical (CVSS 9.8): l8w8jwt 2.2.1 uses memcmp (which is not constant time) to verify authentication, which makes it easier to bypass…
Browse all CWE-203 (Observable Discrepancy) vulnerabilities →