Skip to content
Fencer Vulns
medium 4.2

CVE-2026-41839 json

Spring Framework Escalation via Session Fixation in WebFlux

published 2026-06-09 5 mo ago modified 2026-09-10 1 mo ago also GHSA-4hfh-6x8g-gwpp , EUVD-2026-35326

cvss
4.2
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 11%
public exploits
0
none known

Summary

A WebFlux application with a compromised subdomain (for example, compromised via cross-site scripting (XSS)) is vulnerable to an escalation attack exchanging a known session ID for that of an authenticated user.

Affected versions: Spring Framework 7.0.0 through 7.0.7; 6.2.0 through 6.2.18; 6.1.0 through 6.1.27; 5.3.0 through 5.3.48.

Patch / fix

  • maven org.springframework:spring-webflux 6.2.19, 7.0.8
  • Spring Spring Framework 5.3.49, 6.1.28, 6.2.18.1, 7.0.7.1

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-2026-41839 updated cvss 4.2

spring-framework: Spring Framework: Privilege escalation via session ID exchange in WebFlux applications

  • Red Hat OpenShift Developer Tools and Services spring-web 6.2.14 Red Hat OpenShift Dev Spaces spring-web 6.2.14
    affected: workaround, no fix available “Fix deferred”

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
5 mo ago

Exploit prediction

0.21% chance of exploitation in the next 30 days, higher than 11% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N
GitHub 3.1 4.2 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
maven org.springframework:spring-webflux
>=7.0.0, <7.0.8
>=6.2.0, <6.2.19
>=6.1.0, <=6.1.21
<=5.3.39
7.0.8
6.2.19

Affected products

  • Spring Spring Framework

Classification

Weakness
Technology feeds

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.