Vulnerability-Lookup

CVE-2026-62959 (GCVE-0-2026-62959)

Vulnerability from cvelistv5 – Published: 2026-07-31 19:57 – Updated: 2026-07-31 23:34

Title

Coturn: Pre-authentication heap memory disclosure in ACME redirect (`try_acme_redirect`)

Summary

Coturn is a free open source implementation of TURN and STUN Server. From 4.5.2 through 4.14.0, when Coturn is started with --acme-redirect <URL> and exposes a plaintext-TCP listener, an unauthenticated remote client can send a single ordinary HTTP GET request and receive a 301 response whose Location header contains up to ~870 bytes of adjacent process heap memory. The leaked region is a recycled network receive buffer that is reused without being zeroed, so on a busy server it can contain data from other clients' requests (TURN credentials, OAuth tokens, relayed payloads). Root cause is a signed→unsigned conversion. This issue is fixed in version 4.15.0.

Severity

8.2 (High)


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

SSVC

Exploitation: poc Automatable: yes Technical Impact: partial

CISA Coordinator (v2.0.3)

CWE

CWE-125 - Out-of-bounds Read
CWE-195 - Signed to Unsigned Conversion Error

Assigner

GitHub_M

References

4 references

URL	Tags
https://github.com/coturn/coturn/security/advisor…	x_refsource_CONFIRM
https://github.com/coturn/coturn/pull/1965	x_refsource_MISC
https://github.com/coturn/coturn/commit/960835886…	x_refsource_MISC
https://github.com/coturn/coturn/releases/tag/4.15.0	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
coturn	coturn	Affected: >= 4.5.2, < 4.15.0

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-62959 (GCVE-0-2026-62959)

Tags

Sightings

Nomenclature