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Fencer Vulns
medium 6.9

CVE-2026-41253 json

In iTerm2 through 3.6.9, displaying a .txt file can cause code execution via DCS 2000p and OSC 135 data, if the working directory contains…

published 2026-04-18 6 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-23656

cvss
6.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 9%
public exploits
0
none known

Summary

In iTerm2 through 3.6.9, displaying a .txt file can cause code execution via DCS 2000p and OSC 135 data, if the working directory contains a malicious file whose name is valid output from the conductor encoding path, such as a pathname with an initial ace/c+ substring, aka "hypothetical in-band signaling abuse." This occurs because iTerm2 accepts the SSH conductor protocol from terminal output that does not originate from a legitimate conductor session.

Patch / fix

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
6 mo ago

Exploit prediction

0.20% chance of exploitation in the next 30 days, higher than 9% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • blog.calif.io https://blog.calif.io/p/mad-bugs-even-cat-readmetxt-is-not referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 6.9 CVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
NVD 3.1 7.8 CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

  • iTerm2 iTerm2

Classification

Weakness
  • CWE-829 Inclusion of Functionality from Untrusted Control Sphere

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.