CVE-2018-16253 json
In sig_verify() in x509.c in axTLS version 2.1.3 and before, the PKCS#1 v1.5 signature verification does not properly verify the ASN.1 meta…
published 2018-11-07 8 y ago modified 2026-06-17 4 mo ago also EUVD-2018-8105
- cvss
- 5.9
- version 3.0, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.6%
- EPSS 0.6% chance of exploitation in 30 days, percentile 49%
- public exploits
- 0
- none known
Summary
In sig_verify() in x509.c in axTLS version 2.1.3 and before, the PKCS#1 v1.5 signature verification does not properly verify the ASN.1 metadata. Consequently, a remote attacker can forge signatures when small public exponents are being used, which could lead to impersonation through fake X.509 certificates. This is an even more permissive variant of CVE-2006-4790 and CVE-2014-1568.
Patch / fix
Exploit prediction
0.62% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- sourceforge.net https://sourceforge.net/p/axtls/mailman/message/36459928/ referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.0 | 5.9 | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N |
| NVD | 2.0 | 4.3 | AV:N/AC:M/Au:N/C:N/I:P/A:N |
Classification
- Weakness
-
- CWE-347 Improper Verification of Cryptographic Signature
References
-
github.com
/igrr/axtls-8266/commit/5efe2947ab45e81d84b5f707c51d1c64be52f36c
patch, third-party-advisory
-
sourceforge.net
/p/axtls/mailman/message/36459928/
mailing-list, exploit, third-party-advisory
Sources
- CVE List CVE-2018-16253
- NVD CVE-2018-16253
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.