CVE-2026-50643
CVE-2026-50643 is a medium-severity vulnerability with a CVSS 4.0 base score of 5.1. 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-125.
Key facts
- Severity: Medium (CVSS 4.0 base score 5.1)
- EPSS exploit prediction: 0% (4th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-37865
- Weakness: CWE-125
- Published:
- Last modified:
Description
8cc is vulnerable to an Out‑of‑Bounds Read due to improper handling of #line directives and GNU linemarkers. The compiler accepts attacker-controlled filename and line number metadata and later uses it without validation when accessing source line arrays. By supplying invalid or oversized line numbers, an attacker can trigger out-of-bounds memory access and a crash. Maintainer of this project was notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Version corresponding to the commit b480958 was tested and confirmed as vulnerable, other versions were not tested but might also be vulnerable.
Frequently asked questions
- What is CVE-2026-50643?
- 8cc is vulnerable to an Out‑of‑Bounds Read due to improper handling of #line directives and GNU linemarkers. The compiler accepts attacker-controlled filename and line number metadata and later uses it without validation when accessing source line arrays. By supplying invalid or oversized line numbers, an attacker can trigger out-of-bounds memory access and a crash. Maintainer of this project was notified early about this vulnerability, but didn't respond with the details of vulnerability or vulnerable version range. Version corresponding to the commit b480958 was tested and confirmed as vulnerable, other versions were not tested but might also be vulnerable.
- How severe is CVE-2026-50643?
- CVE-2026-50643 has a CVSS 4.0 base score of 5.1, rated medium severity.
- Is CVE-2026-50643 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (4th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-50643?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
- Does CVE-2026-50643 have an EU (EUVD) identifier?
- Yes. CVE-2026-50643 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37865.
- When was CVE-2026-50643 published?
- CVE-2026-50643 was published on 2026-06-18 and last updated on 2026-06-22.
References
Other CWE-125 (Out-of-bounds Read) vulnerabilities
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