SB20260422206 - Off-by-one in yauzl
Published: April 22, 2026
Security Bulletin ID
SB20260422206
Severity
Low
Patch available
YES
Number of vulnerabilities
1
Exploitation vector
Remote access
Highest impact
Denial of service
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 1 security vulnerability.
1) Off-by-one (CVE-ID: CVE-2026-31988)
The vulnerability allows a remote attacker to perform a denial of service attack.
The vulnerability exists due to an off-by-one error in the NTFS extended timestamp extra field parser within the getLastModDate() function. The while loop condition checks cursor < data.length + 4 instead of cursor + 4 <= data.length, allowing readUInt16LE() to read past the buffer boundary. A remote attacker can cause a denial of service (process crash via ERR_OUT_OF_RANGE exception) by sending a crafted zip file with a malformed NTFS extra field.
Remediation
Install update from vendor's website.
References
- https://github.com/thejoshwolfe/yauzl/commit/c4695215b05c6adffda613b9051a2a85429b33fe
- https://www.codeant.ai/security-research/yauzl-denial-of-service-zip-file-crash
- https://www.npmjs.com/package/yauzl
- https://www.vulncheck.com/advisories/yauzl-denial-of-service-via-off-by-one-error-in-ntfs-timestamp-parser