GPUStack: SAML callback trusts an unverified SAMLResponse, allowing authentication bypass and account takeover
Affects GPUStack 0.7.1 up to but not including 2.2.2 where the /auth/saml/callback endpoint is network-reachable. Fixed in 2.2.2.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 2.2.2
- Who is exposed
- Default setups
Do first: Check every install: default setups are affected.
- Exploitation?/40Exploitation: unknown (data gap). No CISA SSVC exploitation rating yet
- Exposure22/25Default setups, reachable over the network without a login
- Reach?/20Reach: unknown (data gap). No tracked technology or package matched
- Severity9.1/10CVSS 9.1
- No patch0/5No signal
What would change the score
- Would score about 71 if added to CISA KEV
- Would score about 66 if CISA's SSVC rates exploitation active
CVE-2026-102894 is not in CISA's Known Exploited Vulnerabilities (KEV) catalog. No public exploit code is tracked. It is rated CVSS 9.1 (critical) and affects gpustack; fixed in 2.2.2.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 31/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Default setups
- Fix
- Fixed in 2.2.2
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
GPUStack, an open-source GPU cluster manager for AI model serving, has a flaw in its SAML login callback that lets a remote attacker without logging in take over user accounts, including administrator accounts, and create new non-administrator accounts. The bug is reached over the network and affects versions from 0.7.1 up to 2.2.2 but not 2.2.2 itself, which contains the fix.
Read the original description
GPUStack is an open-source GPU cluster manager for AI model serving and GPU instance provisioning. From 0.7.1 until 2.2.2, the /auth/saml/callback endpoint decoded SAML XML, used its NameID and attributes to resolve or provision a user, and minted a gpustack_session JWT without calling OneLogin_Saml2_Auth.process_response to verify the signature, issuer, audience, destination, or time conditions. Any network client could submit an identity for an existing user, including an administrator, or provision a new non-administrator account, even when SAML was not configured. Response and Assertion identifiers were not consumed, so captured signed responses could also be replayed. This issue is fixed in version 2.2.2.
What to do
Check every install: default setups are affected.
Upgrade to a fixed version: 2.2.2.
Workaround: Block network access to /auth/saml/callback (e.g. at a reverse proxy / ingress) until upgraded.
Timeline
- CVE published
- First seen by cve.now
- Posted on X by cve.now
Affected versions
- gpustack gpustack
From 0.7.1 · fixed in 2.2.2
Evidence 6
- Advisory
- Repository
- Repository
- Repository
- Repository
- Repository
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-102894
Is CVE-2026-102894 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
The SAML callback accepts a SAMLResponse without verifying it, so a forged or captured response can produce a valid session. If the name matches an existing user, such as an administrator, the attacker gets that user's session, which is full account takeover. Otherwise a new non-admin account can be provisioned.Source: github.com
Which versions are affected by CVE-2026-102894?
gpustack: from 0.7.1 before 2.2.2.Source: cve.now feed data
Am I affected, and how do I check?
GPUStack versions from 0.7.1 up to but not including 2.2.2 are in the affected range. Exposure also depends on whether the /auth/saml/callback endpoint can be reached over the network. Check the installed version against that range and check whether that endpoint is reachable from your network.Source: github.com
How do I fix CVE-2026-102894?
Upgrade GPUStack to 2.2.2 or later, which fixes the issue.Source: github.com