CVE-2026-54891

NameCVE-2026-54891
DescriptionImproper Enforcement of Message Integrity During Transmission in a Communication Channel vulnerability in Erlang/OTP ssl (tls_gen_connection module) allows a network-positioned attacker to inject unauthenticated plaintext that the TLS client application later treats as authenticated server data. The function tls_gen_connection:handle_protocol_record/3 rejects APPLICATION_DATA records that arrive in pre-handshake states when the TLS endpoint acts as a server, but does not apply the same check when the endpoint acts as a client. A network-positioned attacker can send plaintext APPLICATION_DATA records to the client during the handshake. The records are buffered and, once the handshake completes successfully, delivered to the application as if they were authenticated post-handshake data. The attacker cannot observe the client's response or steer the connection, so the impact is limited to blind injection of unauthenticated bytes. The injection window is wider for TLS versions prior to TLS 1.3 than for TLS 1.3. This vulnerability is associated with program file lib/ssl/src/tls_gen_connection.erl. This issue affects OTP from OTP 17.0 before 29.0.3, 28.5.0.3 and 27.3.4.14 corresponding to ssl from 5.3.4 before 11.7.3, 11.6.0.3 and 11.2.12.10. TLS 1.3 is affected starting with OTP 22.0, when TLS 1.3 support was added.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
erlang (PTS)bullseye1:23.2.6+dfsg-1+deb11u1vulnerable
bullseye (security)1:23.2.6+dfsg-1+deb11u4vulnerable
bookworm1:25.2.3+dfsg-1+deb12u4vulnerable
bookworm (security)1:25.2.3+dfsg-1+deb12u1vulnerable
trixie1:27.3.4.1+dfsg-1+deb13u2vulnerable
forky, sid1:29.0.2+dfsg-1vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
erlangsource(unstable)(unfixed)

Notes

https://github.com/erlang/otp/security/advisories/GHSA-gf6r-99xw-6qg6
https://cna.erlef.org/cves/CVE-2026-54891.html
https://osv.dev/vulnerability/EEF-CVE-2026-54891
https://github.com/erlang/otp/commit/07d2d0e93f6aaf7652a81e8df075fc1728da5e96 (OTP-29.0.3, OTP-28.5.0.3, OTP-27.3.4.14)

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