GHSA-6gc3-crp7-25w5 is a medium-severity (CVSS 5.3) CWE-409 vulnerability in github.com/russellhaering/gosaml2. A fix is available for github.com/russellhaering/gosaml2 — see the affected versions and patch details below.
gosaml2 vulnerable to Denial Of Service Via Deflate Decompression Bomb
Exploitation Status
No confirmed exploitation observed yet
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-6gc3-crp7-25w5.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-6gc3-crp7-25w5 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/russellhaering/gosaml2Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Impact
SAML Service Providers using this library for SAML authentication support are likely susceptible to Denial of Service attacks. A bug in this library enables attackers to craft a deflate-compressed request which will consume significantly more memory during processing than the size of the original request. This may eventually lead to memory exhaustion and the process being killed.
Mitigation
The maximum compression ratio achievable with deflate is 1032:1, so by limiting the size of bodies passed to gosaml2, limiting the rate and concurrency of calls, and ensuring that lots of memory is available to the process it may be possible to help Go's garbage collector "keep up".
Implementors are encouraged not to rely on this.
Patches
This issue is addressed in v0.9.0
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/russellhaering/gosaml2 | all versions | 0.9.0go get github.com/russellhaering/gosaml2@v0.9.0 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/russellhaering/gosaml2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/russellhaering/gosaml2 to 0.9.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-6gc3-crp7-25w5 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-6gc3-crp7-25w5 can be triaged on real exposure rather than presence alone.
Tailored to GHSA-6gc3-crp7-25w5. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-6gc3-crp7-25w5 in your dependencies?
O3 Security finds GHSA-6gc3-crp7-25w5 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.