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Fencer Intel
medium 6.8

CVE-2020-24613 json

wolfSSL before 4.5.0 mishandles TLS 1.3 server data in the WAIT_CERT_CR state, within SanityCheckTls13MsgReceived() in tls13.c.

published 6y ago modified 4mo ago also EUVD-2020-17330

cvss
6.8
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.9%
EPSS 0.9% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

wolfSSL before 4.5.0 mishandles TLS 1.3 server data in the WAIT_CERT_CR state, within SanityCheckTls13MsgReceived() in tls13.c. This is an incorrect implementation of the TLS 1.3 client state machine. This allows attackers in a privileged network position to completely impersonate any TLS 1.3 servers, and read or modify potentially sensitive information between clients using the wolfSSL library and these TLS servers.

Patch / fix

  • wolfssl wolfssl 4.5.0
  • wolfssl Debian 13, Debian 12 4.5.0+dfsg-1

debian advisories DEBIAN-CVE-2020-24613

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Exploit prediction

0.86% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • research.nccgroup.com https://research.nccgroup.com/2020/08/24/technical-advisory-wolfssl-tls-1-3-client-man-in-the-middle-attack/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.8 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:N
NVD 2.0 4.9 AV:N/AC:M/Au:S/C:P/I:P/A:N

Classification

Weakness
  • CWE-295 Improper Certificate Validation

References

Sources

Fencer Intel 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.