CVE-2020-8955

irc_mode_channel_update in plugins/irc/irc-mode.c in WeeChat through 2.7 allows remote attackers to cause a denial of service (buffer overflow and application crash) or possibly have unspecified other impact via a malformed IRC message 324 (channel mode).

Published: 2020-02-12 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-8955 is rated High Risk (67.2/100): CVSS Critical severity, with high exploitation likelihood (EPSS 9.66%, 93th percentile). EPSS ranks this CVE among the most likely to be exploited in the near term. High exploitation likelihood—assess exposure and prioritize remediation.

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-2020-8955

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 2026-05-27 14.21% 9.66% -4.55%
2 2025-11-21 8.38% 14.21% +5.83%
3 2025-11-18 — 8.38% —

Full EPSS history (24 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-8955

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2020-8955

OS Trackers for CVE-2020-8955

vendor priority summary link
alpine critical CVE-2020-8955: 1 source package rows (weechat); 11 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 4. https://security.alpinelinux.org/vuln/CVE-2020-8955
debian not yet assigned CVE-2020-8955 not yet assigned priority: Debian including 1 source packages (weechat), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-8955
gentoo low CVE-2020-8955: 1 GLSA(s) (202003-51), 1 atom(s) (net-irc/weechat); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-8955
ubuntu medium CVE-2020-8955 medium priority: Ubuntu including 1 source packages (weechat), 12 status rows across 12 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, trusty, upstream, xenial): ignored 5, not-affected 3, released 2, DNE 1, needs-triage 1. https://ubuntu.com/security/CVE-2020-8955

Affected software / configurations for CVE-2020-8955

Vendor Product Version Raw CPE
weechat weechat >= 0.3.8, <= 2.7 cpe:2.3:a:weechat:weechat:*:*:*:*:*:*:*:*
fedoraproject fedora 30 cpe:2.3:o:fedoraproject:fedora:30:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
opensuse backports_sle 15.0 cpe:2.3:a:opensuse:backports_sle:15.0:-:*:*:*:*:*:*
opensuse backports_sle 15.0 cpe:2.3:a:opensuse:backports_sle:15.0:sp1:*:*:*:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

References for CVE-2020-8955

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2020-02/msg00032.html Mailing List Third Party Advisory
https://github.com/weechat/weechat/commit/6f4f147d8e86adf9ad34a8ffd7e7f1f23a7e74da Patch Third Party Advisory
https://lists.debian.org/debian-lts-announce/2020/03/msg00031.html Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/09/msg00018.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4ASRTCQFFDAAK347URWNDH6NSED2BGNY/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ER23GT23US5JXDLUZAMGMWXKZ74MI4S2/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M3LAJTLI3LWZRNCFYJ7PCBBTHUMCCBHH/
https://security.gentoo.org/glsa/202003-51 Third Party Advisory
https://weechat.org/doc/security/ Vendor Advisory
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