Source: erlang-cowlib Version: 2.19.0-1 Severity: important Tags: security upstream X-Debbugs-Cc: [email protected], Debian Security Team <[email protected]>
Hi, The following vulnerability was published for erlang-cowlib. CVE-2026-43971[0]: | Improper Encoding or Escaping of Output vulnerability in ninenines | cowlib allows Link header directive smuggling via unescaped special | characters in cow_link:link/1. cow_link:do_link/1 in cowlib | interpolates the target URI, rel value, and attribute keys directly | into the serialized Link: header value without escaping or token- | grammar validation. A > byte in target prematurely closes the URI | slot, allowing an attacker to append additional link entries with | attacker-chosen rel directives. A " or \ in rel escapes the quoted | string and opens new parameters. Any byte — including whitespace, =, | and " — in an attribute key is emitted verbatim. Because browsers | act on Link: directives such as rel="preconnect", rel="preload", and | rel="prerender", an attacker who can influence these fields in an | application that round-trips parsed Link headers through | cow_link:link/1 can force victim browsers to make out-of-band | connections to attacker-controlled origins. This issue affects | cowlib: from 2.9.0 onward. If you fix the vulnerability please also make sure to include the CVE (Common Vulnerabilities & Exposures) id in your changelog entry. For further information see: [0] https://security-tracker.debian.org/tracker/CVE-2026-43971 https://www.cve.org/CVERecord?id=CVE-2026-43971 [1] https://cna.erlef.org/cves/CVE-2026-43971.html [2] https://osv.dev/vulnerability/EEF-CVE-2026-43971 [3] https://github.com/ninenines/cowlib/commit/89da27ee4c241f5d649ba7d9b7f2188918af6cea Regards, Salvatore
