{"cve":"CVE-2026-26309","nvd":{"published":"2026-03-10T20:16:35.880","modified":"2026-06-17T10:26:03.940","status":"Analyzed","description":"Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, an off-by-one write in Envoy::JsonEscaper::escapeString() can corrupt std::string null-termination, causing undefined behavior and potentially leading to crashes or out-of-bounds reads when the resulting string is later treated as a C-string. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","score":5.3},"cwes":["CWE-193"],"references":["https://github.com/envoyproxy/envoy/security/advisories/GHSA-56cj-wgg3-x943"],"products":["envoyproxy:envoy"],"source":"nvd","synced_at":"2026-10-19T22:25:53.701907451+00:00"},"epss":{"cve":"CVE-2026-26309","score":0.00388,"percentile":0.32892,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-56cj-wgg3-x943","url":"https://osv.dev/vulnerability/GHSA-56cj-wgg3-x943","summary":"Envoy affected by off-by-one write in JsonEscaper::escapeString()","modified":"2026-03-13T20:26:07.599912Z","packages":[{"ecosystem":"Go","name":"github.com/envoyproxy/envoy","purl":"pkg:golang/github.com/envoyproxy/envoy","ranges":["1.37.0"],"fixed":[]},{"ecosystem":"Go","name":"github.com/envoyproxy/envoy","purl":"pkg:golang/github.com/envoyproxy/envoy","ranges":[">=1.36.0 <=1.36.4"],"fixed":[]},{"ecosystem":"Go","name":"github.com/envoyproxy/envoy","purl":"pkg:golang/github.com/envoyproxy/envoy","ranges":[">=1.35.0 <=1.35.8"],"fixed":[]},{"ecosystem":"Go","name":"github.com/envoyproxy/envoy","purl":"pkg:golang/github.com/envoyproxy/envoy","ranges":["<=1.34.12"],"fixed":[]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}