CVE-2021-3404
In ytnef 1.9.3, the SwapWord function in lib/ytnef.c allows remote attackers to cause a denial-of-service (and potentially code execution) due to a heap buffer overflow which can be triggered via a crafted file.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (1.94%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In ytnef 1.9.3, the SwapWord function in lib/ytnef.c allows remote attackers to cause a denial-of-service (and potentially code execution) due to a heap buffer overflow which can be triggered via a crafted file.
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- EPSS
- 1.94% probability · 80th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-119, CWE-787
- Affected
- ytnef project/ytnef · redhat/enterprise linux · fedoraproject/fedora
- Source
- secalert@redhat.com
EPSS 1.9% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.redhat.com/show_bug.cgi?id=1926965Issue Tracking, Third Party Advisory
- https://github.com/Yeraze/ytnef/issues/86Exploit, Issue Tracking, Third Party Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1926965Issue Tracking, Third Party Advisory
- https://github.com/Yeraze/ytnef/issues/86Exploit, Issue Tracking, Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.