Quick answers
- Is CVE-2026-73252 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-73252 being exploited in the wild.
- How severe is CVE-2026-73252?
- High severity, with a CVSS score of 7.5, published 14 October 2026.
- Which products and versions are affected?
- Cesanta Mongoose before 7.23.
- Is there a fix for CVE-2026-73252?
- Yes: fixed in 7.23. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-73252 attacked?
- It is attacked over the network, in a software library.
- Am I affected by CVE-2026-73252?
- Check whether you run Cesanta Mongoose 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.
How to fix
- Fixed in: 7.23
Technical details
A vulnerability in the mg_tls_recv_record() function in src/tls_builtin.c allows TLS 1.3 records with a decrypted size of exactly 16 bytes (the authentication tag length) to pass validation, causing integer underflow in the recv_len calculation that sets it to SIZE_MAX. An unauthenticated network attacker can trigger this before certificate or Finished message validation to read stale heap buffer contents, causing denial of service or potential information disclosure.
Affected products
- Cesanta Mongoose before 7.23
Timeline
- 2026-10-14: disclosed