Vulnerability · Published Oct 15, 2026 · Assigned by VulnCheck
CVE-2026-111146ytnef through 2.1.2 Heap Out-of-Bounds Read via MAPIPrint in lib/ytnef.c
Medium 6.1
In plain English
A medium-severity out-of-bounds read in ytnef from Yeraze. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 2% of all known vulnerabilities).
Severity (CVSS 3.1)6.1Medium
Exploit odds (30 days)0.1%top 97.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
ytnef through 2.1.2 contains a heap out-of-bounds read vulnerability in MAPIPrint() that allows attackers to read past heap allocations by supplying compressed RTF properties. Attackers can deliver a crafted winmail.dat whose decompressed RTF lacks a NUL terminator, causing printf to over-read, crashing ytnefprint and leaking adjacent heap bytes.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libytnef | no fix listed | DEBIAN-CVE-2026-111146 |
| Debian:13 | libytnef | no fix listed | DEBIAN-CVE-2026-111146 |
| Debian:14 | libytnef | no fix listed | DEBIAN-CVE-2026-111146 |
| Ubuntu:22.04:LTS | libytnef | no fix listed | UBUNTU-CVE-2026-111146 |
| Ubuntu:24.04:LTS | libytnef | no fix listed | UBUNTU-CVE-2026-111146 |
| Ubuntu:26.04:LTS | libytnef | no fix listed | UBUNTU-CVE-2026-111146 |
| Ubuntu:26.10 | libytnef | no fix listed | UBUNTU-CVE-2026-111146 |
Affected products (as reported)
Weakness: CWE-125 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
References
- https://hackmd.io/@haind-pwn/ytnef-decompressrtf-oob-read technical-description, exploit
- https://github.com/Yeraze/ytnef/issues/112 issue-tracking
- https://github.com/Yeraze/ytnef/blob/d9f089144414d3b0912c29ab96f8f1c591d00319/lib/ytnef.c#L1449-L1458 technical-description
- https://github.com/Yeraze/ytnef/blob/d9f089144414d3b0912c29ab96f8f1c591d00319/lib/ytnef.c#L1605-L1614 technical-description
- https://github.com/Yeraze/ytnef product
- VulnCheck Advisory: ytnef through 2.1.2 Heap Out-of-Bounds Read via MAPIPrint in lib/ytnef.c third-party-advisory