Quick answers
- Is CVE-2026-63626 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-63626 being exploited in the wild.
- How severe is CVE-2026-63626?
- High severity, with a CVSS score of 8.8, published 14 October 2026.
- Which products and versions are affected?
- Cesanta Mongoose before 7.23.
- Is there a fix for CVE-2026-63626?
- Yes: fixed in 7.23. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-63626 attacked?
- It is attacked from the adjacent network, in a software library.
- Am I affected by CVE-2026-63626?
- 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
The ppp_handle_ipv6cp() function in src/l2_ppp.c fails to validate that the 16-bit IPv6CP length field matches the actual payload size before using it to read and write buffer data. An unauthenticated adjacent peer on a PPP or PPPoE link can complete the LCP handshake and send a Configure-Request with an oversized length value, causing out-of-bounds reads from recv_queue.buf and writes to tx.buf. The same vulnerability allows heap information disclosure via find_opt() and denial of service through event loop hangs.
Affected products
- Cesanta Mongoose before 7.23
Timeline
- 2026-10-14: advisory