CVE-2026-53779
CVE-2026-53779 is a high-severity vulnerability 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-22.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v4: 8.7
- EPSS exploit prediction: 0% (33rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-38340
- Weakness: CWE-22
- Published:
- Last modified:
Description
WebP Server Go through 0.14.4 contains a path traversal vulnerability on Windows that allows unauthenticated attackers to read files outside the configured IMG_PATH directory by sending requests with percent-encoded backslashes (%5C) that bypass the path.Clean() sanitization in handler/router.go. Attackers can exploit the discrepancy between Go's forward-slash-only path normalization and Windows file system APIs that treat backslashes and forward slashes as equivalent to access arbitrary files on the host filesystem accessible to the server process.
Frequently asked questions
- What is CVE-2026-53779?
- WebP Server Go through 0.14.4 contains a path traversal vulnerability on Windows that allows unauthenticated attackers to read files outside the configured IMG_PATH directory by sending requests with percent-encoded backslashes (%5C) that bypass the path.Clean() sanitization in handler/router.go. Attackers can exploit the discrepancy between Go's forward-slash-only path normalization and Windows file system APIs that treat backslashes and forward slashes as equivalent to access arbitrary files on the host filesystem accessible to the server process.
- How severe is CVE-2026-53779?
- CVE-2026-53779 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-2026-53779 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (33rd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-53779?
- 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-2026-53779 have an EU (EUVD) identifier?
- Yes. CVE-2026-53779 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-38340.
- When was CVE-2026-53779 published?
- CVE-2026-53779 was published on 2026-06-22 and last updated on 2026-06-23.
References
- https://github.com/webp-sh/webp_server_go/commit/eb3b5f9289b331cb639cd610b0d1c532d2cc24e0
- https://github.com/webp-sh/webp_server_go/pull/451
- https://www.vulncheck.com/advisories/webp-server-go-path-traversal-via-backslash-encoding-on-windows
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