Skip to content
Fencer Intel
high 7.7

CVE-2026-126308 json

Coder 2.38.0 before 2.38.2 Session Token Leak via Sub-Agent External Apps

published 19d ago modified 2d ago also EUVD-2026-125212 , GHSA-2x8w-q434-f76p

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository coder/coder. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 24%
public exploits
0
none known

Summary

The web dashboard in Coder 2.24.0 before 2.29.23, 2.30.0 before 2.34.14, 2.35.0 before 2.36.9, 2.37.0 before 2.37.6, and 2.38.0 before 2.38.2 replaces the $SESSION_TOKEN placeholder in external app URLs with a full-access API key without checking whether the app belongs to a sub-agent. Code running in a workspace can register a disguised sub-agent app with a custom protocol URL, so the owner's click sends their API key to an attacker-chosen destination.

Patch / fix

  • coder coder 2.29.23, 2.34.14, 2.36.0, 2.36.9, 2.37.6, 2.38.2

Is CVE-2026-126308 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 24% of all scored CVEs (FIRST EPSS, 2026-11-14).

CVSS scores

assigned by version score vector
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N
CNA 3.1 7.7 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
CNA 4.0 8.7 CVSS:4.0/AV:N/AC:H/AT:P/PR:L/UI:P/VC:H/VI:H/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 7.7 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N

Affected products

  • coder coder

Classification

Weakness
  • CWE-201 Insertion of Sensitive Information Into Sent Data

References

Sources

Fencer Intel 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.

The maintainers of coder/coder published their own advisory on GitHub. Reviewed sources take precedence over it.