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Fencer Vulns
medium 4.7

CVE-2018-16868 json

A Bleichenbacher type side-channel based padding oracle attack was found in the way gnutls handles verification of RSA decrypted PKCS#1 v1.…

published 2018-12-03 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-8659

cvss
4.7
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 47%
public exploits
0
none known

Summary

A Bleichenbacher type side-channel based padding oracle attack was found in the way gnutls handles verification of RSA decrypted PKCS#1 v1.5 data. An attacker who is able to run process on the same physical core as the victim process, could use this to extract plaintext or in some cases downgrade any TLS connections to a vulnerable server.

Patch / fix

  • gnutls28 Debian 14, Debian 13, Debian 12 3.6.5-2

debian advisories DEBIAN-CVE-2018-16868

  • gnutls SLE Module for Desktop Applications 15, SLE Module for Basesystem 15 SP1, SLE Module for Basesystem 15 3.6.7-6.11.1
  • gnutls SLE Module for Desktop Applications 15, SLE Module for Basesystem 15 3.6.7-6.8.1

suse advisories SUSE-SU-2019:1351-2SUSE-SU-2019:1351-1SUSE-SU-2019:1121-1

  • gnutls openSUSE Leap 15.1, openSUSE Leap 15.0 3.6.7-lp151.2.3.1
  • gnutls openSUSE Leap 15.0 3.6.7-lp150.9.1

opensuse advisories openSUSE-SU-2019:1477-1openSUSE-SU-2019:1353-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2018-16868 updated cvss 4.7

gnutls: Bleichenbacher-like side channel leakage in PKCS#1 v1.5 verification and padding oracle verification

  • Red Hat Enterprise Linux 5 gnutls Red Hat Enterprise Linux 6 gnutls, gnutls-guile, gnutls-utils Red Hat Enterprise Linux 7 gnutls, gnutls-c++, gnutls-dane, gnutls-utils Red Hat Virtualization 4 rhvm-appliance, redhat-virtualization-host-image-update
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 8 gnutls, gnutls-c++, gnutls-dane, gnutls-utils, mingw-gnutls, mingw32-gnutls, +1 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.58% chance of exploitation in the next 30 days, higher than 47% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.0 4.7 CVSS:3.0/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N
NVD 3.1 5.6 CVSS:3.1/AV:P/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N
NVD 2.0 3.3 AV:L/AC:M/Au:N/C:P/I:P/A:N

Affected products

  • [UNKNOWN] gnutls

Classification

Weakness

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.