CVE-2018-16868

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.

Published: 2018-12-03 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-16868 is rated Low Risk (37.8/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.57%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2018-16868

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.04% 0.57% +0.53%
2 2025-12-03 0.06% 0.04% -0.01%
3 2025-11-21 — 0.06% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-16868

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.6 3.1 MEDIUM
CVSS:3.1/AV:P/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N Click to expand
Attack vector (AV:P)
Hands-on access—USB, keyboard, opening the case—not something you do purely over the wire.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 0.4 4.7 [email protected]
4.7 3.0 MEDIUM
CVSS:3.0/AV:P/AC:H/PR:H/UI:N/S:C/C:H/I:N/A:N Click to expand
Attack vector (AV:P)
Hands-on access—USB, keyboard, opening the case—not something you do purely over the wire.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:H)
They need powerful rights—admin, root, or similar—before this pays off.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 0.3 4.0 [email protected]
3.3 2.0 LOW
AV:L/AC:M/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 3.4 4.9 [email protected]

Weakness enumeration for CVE-2018-16868

OS Trackers for CVE-2018-16868

vendor priority summary link
alpine medium CVE-2018-16868: 1 source package rows (gnutls); 5 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 5. https://security.alpinelinux.org/vuln/CVE-2018-16868
debian not yet assigned CVE-2018-16868 not yet assigned priority: Debian including 1 source packages (gnutls28), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-16868
redhat medium — https://access.redhat.com/security/cve/CVE-2018-16868
suse medium CVE-2018-16868 severity moderate: SUSE including 347 source package names (0.1.0:libgnutls30-3.6.7-6.8.1, 0.1.75:libgnutls30-3.6.7-6.8.1, …), 363 product×package rows across 59 product lines (Container caasp/v4/389-ds, Container caasp/v4/busybox, … (59 product lines)): Fixed 206, Known Affected 157. https://www.suse.com/security/cve/CVE-2018-16868/
ubuntu low CVE-2018-16868 low priority: Ubuntu including 2 source packages (gnutls26, gnutls28), 28 status rows across 14 suites (bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, trusty, upstream, xenial): DNE 13, released 10, ignored 4, needs-triage 1. https://ubuntu.com/security/CVE-2018-16868

Affected software / configurations for CVE-2018-16868

Vendor Product Version Raw CPE
gnu gnutls <= 3.6.4 cpe:2.3:a:gnu:gnutls:*:*:*:*:*:*:*:*

References for CVE-2018-16868

URL Tags
http://cat.eyalro.net/ Technical Description Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00017.html Broken Link Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00068.html Broken Link Mailing List Third Party Advisory
http://www.securityfocus.com/bid/106080 Third Party Advisory VDB Entry
https://bugzilla.redhat.com/show_bug.cgi?id=CVE-2018-16868 Issue Tracking Third Party Advisory
cvelogic Threat Intelligence