Bug 2496799 - CVE-2026-55952 erlang: Erlang/OTP: Denial of Service in TLS 1.3 session ticket handling [epel-all]
Summary: CVE-2026-55952 erlang: Erlang/OTP: Denial of Service in TLS 1.3 session ticke...
Keywords:
Status: CLOSED WONTFIX
Alias: None
Product: Fedora EPEL
Classification: Fedora
Component: erlang
Version: epel10
Hardware: Unspecified
OS: Unspecified
high
high
Target Milestone: ---
Assignee: Richard W.M. Jones
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard: {"flaws": ["e00cbf7d-cacc-4494-a9a2-a...
Depends On:
Blocks: CVE-2026-55952
TreeView+ depends on / blocked
 
Reported: 2026-07-03 09:39 UTC by jkelly
Modified: 2026-07-24 18:33 UTC (History)
4 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed: 2026-07-24 18:33:05 UTC
Type: ---
Embargoed:


Attachments (Terms of Use)

Description jkelly 2026-07-03 09:39:22 UTC
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.

The Erlang/OTP ssl application does not validate that the PSK identity list and binder list carried in a TLS 1.3 ClientHello pre-shared key extension have equal length before passing them to the session ticket handler. In tls_handshake_1_3:handle_pre_shared_key/3, an OfferedPreSharedKeys record with a mismatched number of identities and binders is forwarded directly to tls_server_session_ticket:use/4, which crashes the session ticket handler process.

An unauthenticated remote attacker can send a single crafted ClientHello to a TLS 1.3 server with session tickets enabled (stateful or stateless mode) and permanently disrupt session ticket handling on that listener. New TLS 1.3 handshakes complete but subsequently crash when the server attempts to issue a session ticket, effectively making TLS 1.3 unusable on the affected listener until the ssl application is restarted. TLS 1.2 connections are not affected.

This issue affects OTP from 22.2 before 29.0.3, 28.5.0.3 and 27.3.4.14 corresponding to ssl from 9.5 before 11.7.3, 11.6.0.3 and 11.2.12.10.

Comment 1 Peter Lemenkov 2026-07-10 17:42:06 UTC
This is delivered for EL9/EL10 via the CentOS Messaging SIG rather than EPEL. Backported erlang builds addressing this CVE are being prepared for c9s and c10s (Messaging SIG); users can obtain them with `dnf install centos-release-messaging` (works on CentOS Stream, RHEL, AlmaLinux, and Rocky). The builds are working their way through the SIG testing tag and will reach stable soon enough. Will update once that lands.

Comment 2 Peter Lemenkov 2026-07-24 18:33:05 UTC
Current Erlang builds for EL9 and EL10 are available from the CentOS Messaging SIG, which tracks upstream releases and carries security backports. The current build is erlang-26.2.5.21-4, which addresses this issue.

These packages work on RHEL, CentOS Stream, AlmaLinux, Rocky Linux and other RHEL-compatible distributions:

    dnf install centos-release-messaging
    dnf install erlang

Closing here, as Erlang updates for EL9 and EL10 are delivered through the Messaging SIG. Please reopen if the SIG builds don't cover your case.


Note You need to log in before you can comment on or make changes to this bug.