CVE-2023-49556: YASM · Buffer Overflow
Source CVE Database V5
Not known to be exploited · CVSS 5.5 Medium : upgrade to 1.3.0.86.g9def when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.3.0.86.g9def
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:HExploitation evidence
Disclosed: evidence found.
CVE published 2 Jan 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade yasm/yasm to 1.3.0.86.g9def.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
GitHubyasm/yasmpkg:github/yasm/yasmOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
To mitigate CVE-2023-49556, European organizations should first identify all instances of YASM in their environments, especially in development and security research teams. In the meantime, restrict local access to systems running YASM to trusted users only, and enforce strict user authentication and authorization policies to prevent unauthorized local access. Educate users about the risk of processing untrusted or malicious assembly code inputs that could trigger the vulnerability. Implement application whitelisting and sandboxing techniques to isolate YASM processes and limit the impact of potential crashes. Additionally, integrate monitoring and alerting for abnormal application behavior or crashes related to YASM to enable rapid response. For build and CI/CD pipelines using YASM, consider adding validation steps or alternative tools until a patch is available. Regularly review and update security policies to include controls for development tools vulnerabilities.
Description
Buffer Overflow vulnerability in YASM 1.3.0.86.g9def allows a remote attacker to cause a denial of service via the expr_delete_term function in the libyasm/expr.c component.