CVE-2018-16253

Name: CVE-2018-16253
Creator: NVD / NIST
Published: 2018-11-07T20:29:00.667+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 0.62%

Last modified Jun 17, 2026

CVE-2018-16253 is a vulnerability of currently unknown severity. 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. EPSS estimates a 0.62% chance of exploitation in the next 30 days.

Description

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.

Metrics

EPSS Probability

0.62%

45.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-347

Affected Software

Vendor	Product	Versions
Axtls Project	Axtls	<= 2.1.3

References

https://github.com/igrr/axtls-8266/commit/5efe2947ab45e81d84b5f707c51d1c64be52f36cPatch, Third Party Advisory
https://sourceforge.net/p/axtls/mailman/message/36459928/Exploit, Third Party Advisory
https://github.com/igrr/axtls-8266/commit/5efe2947ab45e81d84b5f707c51d1c64be52f36cPatch, Third Party Advisory
https://sourceforge.net/p/axtls/mailman/message/36459928/Exploit, Third Party Advisory

Timeline

Published: Nov 7, 2018
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2018-16253?

How severe is CVE-2018-16253?

Severity scoring for CVE-2018-16253 is pending analysis. The EPSS model estimates a 0.62% probability of exploitation in the next 30 days.

How do I fix CVE-2018-16253?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2018-16253?

Run a free Strix scan to check your systems for this vulnerability.

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Source: NVD / NIST