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Fencer Intel
medium 6.2

CVE-2026-103957 json

Server-side request forgery in the OAuth2 discovery handling in Loom for AWS

published last mo. modified last mo. also EUVD-2026-91772

cvss
6.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

Server-side request forgery in the OAuth2 discovery handling in Loom for AWS before 1.7.0 might allow an authenticated remote user to obtain the access token of another user of the deployment and to cause the application to issue requests to arbitrary internal network locations, via a crafted discovery document address supplied when registering a tool server or remote agent configured for delegated authentication.

To remediate this issue, users should upgrade to version 1.7.0 or later.

Patch / fix

  • AWS loom 1.7.0

Is CVE-2026-103957 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.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-103957 updated cvss 4.5

loom: loom: Information disclosure via server-side request forgery in OAuth2 discovery

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CNA 3.1 6.2 CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:N/A:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
CNA 4.0 8.2 CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:P/VC:H/VI:N/VA:N/SC:H/SI:N/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

Affected products

  • AWS loom

Classification

Weakness
  • CWE-918 Server-Side Request Forgery
  • 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.