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PatchSiren cyber security CVE debrief

CVE-2017-6301 Debian CVE debrief

CVE-2017-6301 is a high-severity out-of-bounds read in ytnef, the TNEF parsing utility. NVD classifies it as CWE-125 with a CVSS 3.0 score of 7.8, and the attack conditions require local access plus user interaction, but the impact can still be high across confidentiality, integrity, and availability. Because the supplied source corpus shows a version-boundary mismatch between the CVE description and NVD CPE data, verify the installed package version rather than relying on a single cutoff.

Vendor
Debian
Product
CVE-2017-6301
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2017-02-24
Original CVE updated
2026-05-13
Advisory published
2017-02-24
Advisory updated
2026-05-13

Who should care

Administrators and application owners who run ytnef to process Outlook/TNEF attachments should care, especially on Debian systems or any environment where untrusted mail attachments are handled. If ytnef is present in a mail-processing or file-conversion workflow, treat this as a patch-priority item.

Technical summary

The vulnerability is described as an out-of-bounds read related to the upstream patch labeled "4 of 9. Out of Bounds Reads." NVD maps it to CWE-125 and gives the vector CVSS:3.0/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H, indicating a local attack that depends on user interaction and can have high impact. The NVD record’s affected CPEs include ytnef up to 1.9 and Debian Linux 8.0 and 9.0.

Defensive priority

High — prioritize patching if ytnef is installed on any system that processes untrusted TNEF content.

Recommended defensive actions

  • Inventory systems that use ytnef and confirm whether they are within the vulnerable version range described by the CVE and NVD records.
  • Apply the vendor or upstream fix referenced by Debian DSA-3846, the oss-security patch discussion, or the upstream pull request/advisory.
  • Treat TNEF/Outlook attachments as untrusted input and restrict where ytnef is allowed to run.
  • If you maintain Debian-based systems, check whether your package source already includes the security fix or a backport.
  • After patching, re-test any workflows that parse malformed or externally supplied TNEF files.

Evidence notes

Source evidence supports a high-severity parser flaw in ytnef: the CVE description says the issue is in ytnef before 1.9.1 and ties it to patch "4 of 9. Out of Bounds Reads." NVD lists CWE-125 and CVSS 7.8 with AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. References in the corpus include Debian DSA-3846, the oss-security mailing list patch thread, GitHub pull request #27, and the X41 advisory. The corpus also contains a version-boundary discrepancy: the description says before 1.9.1, while NVD CPE data lists ytnef through 1.9 and Debian 8.0/9.0.

Official resources

Publicly disclosed on 2017-02-24. The NVD record was modified later on 2026-05-13, but that modified date is not the original disclosure date.