CVE-2020-18778

Exp

In Libav 12.3, there is a heap-based buffer over-read in vc1_decode_p_mb_intfi in vc1_block.c that allows an attacker to cause denial-of-service via a crafted file.

Published: 2021-08-23 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-18778 is rated High Exploit Risk (60.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.86%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2020-18778

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2020-18778

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 0.48% 0.86% +0.38%
2 2025-11-21 0.29% 0.48% +0.20%
3 2025-11-18 — 0.29% —

Full EPSS history (11 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-18778

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2020-18778

OS Trackers for CVE-2020-18778

vendor priority summary link
ubuntu medium CVE-2020-18778 medium priority: Ubuntu including 1 source packages (libav), 15 status rows across 15 suites (bionic, focal, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): DNE 12, ignored 1, needed 1, needs-triage 1. https://ubuntu.com/security/CVE-2020-18778

Affected software / configurations for CVE-2020-18778

Vendor Product Version Raw CPE
libav libav 12.3 cpe:2.3:a:libav:libav:12.3:*:*:*:*:*:*:*

References for CVE-2020-18778

URL Tags
https://bugzilla.libav.org/show_bug.cgi?id=1155 Broken Link Exploit Issue Tracking Third Party Advisory
https://cwe.mitre.org/data/definitions/126.html Technical Description
cvelogic Threat Intelligence