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Fencer Vulns
medium 4.0

CVE-2019-5101 json

An exploitable information leak vulnerability exists in the ustream-ssl library of OpenWrt, versions 18.06.4 and 15.05.1.

published 2019-11-18 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-14706

cvss
4.0
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 55%
public exploits
0
none known

Summary

An exploitable information leak vulnerability exists in the ustream-ssl library of OpenWrt, versions 18.06.4 and 15.05.1. When connecting to a remote server, the server's SSL certificate is checked but no action is taken when the certificate is invalid. An attacker could exploit this behavior by performing a man-in-the-middle attack, providing any certificate, leading to the theft of all the data sent by the client during the first request.An exploitable information leak vulnerability exists in the ustream-ssl library of OpenWrt, versions 18.06.4 and 15.05.1. When connecting to a remote server, the server's SSL certificate is checked but no action is taken when the certificate is invalid. An attacker could exploit this behavior by performing a man-in-the-middle attack, providing any certificate, leading to the theft of all the data sent by the client during the first request. After an SSL connection is initialized via _ustream_ssl_init, and after any data (e.g. the client's HTTP request) is written to the stream using ustream_printf, the code eventually enters the function _ustream_ssl_poll, which is used to dispatch the read/write events

Exploit prediction

0.75% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • talosintelligence.com https://talosintelligence.com/vulnerability_reports/TALOS-2019-0893 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.0 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:N/A:N
NVD 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:P/I:N/A:N

Affected products

  • OpenWRT OpenWRT

Classification

Weakness
  • CWE-295 Improper Certificate Validation

References

Sources

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.