Quick answers
- Is CVE-2026-62959 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-62959 being exploited in the wild.
- How severe is CVE-2026-62959?
- Informational severity, with a CVSS score of 8.2, published 31 July 2026.
- Which products and versions are affected?
- Coturn >= 4.5.2, < 4.15.0.
- Is there a fix for CVE-2026-62959?
- A patch was published on 2026-06-27: Fix committed to master branch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-62959 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-62959?
- Check whether you run Coturn 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
An out-of-bounds read vulnerability exists in the try_acme_redirect() function of Coturn. The root cause is a signed-to-unsigned conversion error where the integer return value of is_acme_req() (which returns negative values on failure) is stored in a size_t variable. This causes negative values to wrap to large unsigned integers, bypassing length checks and resulting in an un-terminated path string. When this path is later used in a 301 Location header via a %s format specifier, the server reads adjacent heap memory until it encounters a null byte. This can leak recycled network buffers containing sensitive data from other sessions. The issue is fixed in version 4.15.0.
Affected products
- coturn coturn >= 4.5.2, < 4.15.0
Timeline
- 2026-06-27: patched: Fix committed to master branch
- 2026-07-22: advisory: Release 4.15.0 published
- 2026-07-31: disclosed: CVE published to NVD