# CVE-2026-55952: Erlang OTP denial of service in SSL TLS 1.3 session ticket handling

Source: https://junglewise.ai/threats/cve-2026-55952-erlang-otp-denial-of-service-in-ssl-tls-1-3-session-ticket  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-02. Updated: 2026-07-02  
License: CC BY 4.0 with a link back

CVE-2026-55952 · Severity: info · CVSS 8.2 · Published 2026-07-02

A vulnerability in the Erlang/OTP SSL library can allow a remote attacker to crash the component responsible for handling secure session tickets. By sending a specially crafted connection request, an attacker can permanently disrupt the server's ability to process new TLS 1.3 connections that use session tickets. This results in a denial-of-service condition for secure web traffic until the affected application is manually restarted.

Technologies: [Erlang OTP](https://junglewise.ai/threats/technologies/otp), [Erlang Ssl](https://junglewise.ai/threats/technologies/ssl). Vendors: [Erlang](https://junglewise.ai/threats/vendors/erlang).

## Quick answers

**Is CVE-2026-55952 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-55952 being exploited in the wild.

**How severe is CVE-2026-55952?** Informational severity, with a CVSS score of 8.2, published 2 July 2026.

**Which products and versions are affected?** Erlang OTP 22.2 before 29.0.3, 28.5.0.3, and 27.3.4.14; Erlang Ssl 9.5 before 11.7.3, 11.6.0.3, and 11.2.12.10.

**Is there a fix for CVE-2026-55952?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-55952 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-55952?** Check whether you run Erlang OTP or Erlang Ssl at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A denial-of-service vulnerability exists in the Erlang/OTP ssl application due to improper validation of the Pre-Shared Key (PSK) extension in TLS 1.3. Specifically, the function 'tls_handshake_1_3:handle_pre_shared_key/3' does not verify that the PSK identity list and binder list have equal lengths. An unauthenticated remote attacker can exploit this by sending a crafted ClientHello with mismatched list lengths, causing the 'tls_server_session_ticket' process to crash. This permanently disrupts session ticket handling on the affected listener until a restart. The issue is fixed in OTP versions 29.0.3, 28.5.0.3, and 27.3.4.14.

## Affected products

- Erlang OTP 22.2 before 29.0.3, 28.5.0.3, and 27.3.4.14
- Erlang ssl 9.5 before 11.7.3, 11.6.0.3, and 11.2.12.10

## Timeline

- 2026-07-02: advisory
- 2026-07-02: disclosed

## References

- [https://github.com/](https://github.com/)
- [https://cna.erlef.org/cves/CVE-2026-55952.html](https://cna.erlef.org/cves/CVE-2026-55952.html)
- [https://github.com/erlang/otp/commit/2c3e599797644310e5d4aa39c7193420e59dadff](https://github.com/erlang/otp/commit/2c3e599797644310e5d4aa39c7193420e59dadff)
- [https://github.com/erlang/otp/commit/9b5437c72fa3403a75c1aba28e5c532bc191c662](https://github.com/erlang/otp/commit/9b5437c72fa3403a75c1aba28e5c532bc191c662)
- [https://github.com/erlang/otp/commit/e77823e6d980b2ec0b4fe4ea3f2d098ca239e3ce](https://github.com/erlang/otp/commit/e77823e6d980b2ec0b4fe4ea3f2d098ca239e3ce)
- [https://github.com/erlang/otp/security/advisories/GHSA-8c57-44c9-pc59](https://github.com/erlang/otp/security/advisories/GHSA-8c57-44c9-pc59)

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