ytnef through 2.1.2 Heap Out-of-Bounds Read via DecompressRTF

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

ytnef through 2.1.2 contains a heap out-of-bounds read vulnerability in DecompressRTF() in lib/ytnef.c that never validates uncompressedSize for uncompressed RTF streams. Attackers can supply a crafted winmail.dat TNEF attachment with a malicious PT_BINARY MAPI property to crash ytnefprint or libytnef callers and leak adjacent heap memory.

Source published

15 Oct 2026 18:57:36 UTC

Source modified

21 Oct 2026 01:20:26 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 6.9 CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N

CVSS 3.1 · 6.1 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H