TLS/DTLS denial of service via unbounded recursion on cross-signed peer certificate chain

Weakness Type (CWE)

CWE-674 — CWE-674 Uncontrolled Recursion

CAPEC

CAPEC-130 — CAPEC-130 Excessive Allocation

CVSS 4.0 Score

8.7

HIGH

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Vulnerability description

The Erlang/OTP ssl application does not detect cycles when reconstructing an incomplete peer certificate chain during a TLS or DTLS handshake. In ssl_certificate:handle_incomplete_chain/5, the received chain is passed to ssl_certificate:build_certificate_chain/5, which walks issuer relationships via ssl_certificate:do_certificate_chain/7 with no cycle detection and no depth limit. When the peer supplies two mutually cross-signed certificates in unordered form (A issues B, B issues A), the issuer lookup alternates between the two certificates and the pair of functions recurses indefinitely, growing the call stack and chain accumulator without bound.

An unauthenticated remote attacker can send a crafted certificate chain in a TLS or DTLS Certificate handshake message to exhaust available memory and crash the BEAM node. Only a TCP connection and a partial handshake are required; no authentication or completed handshake is needed, and both TLS/DTLS servers and clients are affected when processing peer certificate messages.

This issue affects OTP from OTP 23.2 before OTP 29.0.4, OTP 28.5.0.4 and OTP 27.3.4.15, corresponding to ssl from 10.2 before 11.7.4, 11.6.0.4 and 11.2.12.11.

Affected

`pkg:otp/ssl`

Module	Source File	Routine
`ssl_certificate`	`src/ssl_certificate.erl`	`ssl_certificate:handle_incomplete_chain/5`
		`ssl_certificate:build_certificate_chain/5`
		`ssl_certificate:do_certificate_chain/7`

Status	Type	Version	Changes / Fixed in
affected	otp ^ⓘ	`10.2`	unaffected at `11.7.4` unaffected at `11.6.0.4` unaffected at `11.2.12.11`

`pkg:github/erlang/otp`

Module	Source File	Routine
`ssl_certificate`	`lib/ssl/src/ssl_certificate.erl`	`ssl_certificate:handle_incomplete_chain/5`
		`ssl_certificate:build_certificate_chain/5`
		`ssl_certificate:do_certificate_chain/7`

Status	Type	Version	Changes / Fixed in
affected	otp ^ⓘ	`23.2`	unaffected at `29.0.4` unaffected at `28.5.0.4` unaffected at `27.3.4.15`
affected	git ^ⓘ	`addc42df11`	unaffected at `7db6472017` unaffected at `241d437039` unaffected at `0307bff2c7`

References

Credits

Finder: Lukas Backström
Remediation developer: Ingela Anderton Andin
Remediation reviewer: Dan Gudmundsson
Remediation reviewer: Jakub Witczak
Remediation reviewer: John Högberg

CVE record as JSON: GET /cves/CVE-2026-58227.json
OSV record as JSON: GET /osv/EEF-CVE-2026-58227.json