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VulnerabilityPublished

CVE-2026-6180: PaperCut NG/MF · Time-of-check Time-of-use (TOCTOU) Race Condition

Affects PaperCut NG/MFSource CVE Database V5

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Not known to be exploited · CVSS 4.1 Medium : upgrade to 25.0.10 or 24.1.9 when convenient.

Data as of 1 Nov 2026, 22:58 UTC

CVSS 4.0 base score
4.1Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.3% chance of exploitation in 30 days – higher than 27% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 25.0.10, 24.1.9
CVSS:4.0/AV:P/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:L/SI:L/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 5 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 1 Nov 2026.

What to do

Upgrade PaperCut NG/MF to 25.0.10 or 24.1.9.

Affected software

ProductAffectedFixed in
PaperCutPaperCut NG/MFAffected
  • <25.0.10
Fixed in
  • 25.0.10
PaperCutPaperCut NG/MFAffected
  • <24.1.9
Fixed in
  • 24.1.9

AI-suggested

If you cannot patch yet, organizations should review and potentially disable custom badge-ID post-processing scripts to mitigate the risk of incorrect user login resulting from truncated badge IDs.

Description

A race condition exists in PaperCut MF when processing badge-swipe data from certain HP multifunction devices. Under specific network conditions involving dropped packets and out-of-order sequence counters, the server may incorrectly process fragmented data chunks. If a sequence reset notification fails to reach the server, the server may reject the initial data chunk while erroneously accepting subsequent chunks before a connection reset completes. This leads to the registration of a truncated badge ID string. While this typically results in an authentication failure, the vulnerability is compounded in environments utilizing custom badge-ID post-processing scripts. In such configurations, the truncated string may be transformed into a valid ID belonging to a different user, leading to unauthorized session establishment (Incorrect User Login) on the device.

References

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