gosaml2 vulnerable to Denial Of Service Via Deflate Decompression Bomb

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

5.3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

• CVE-2023-26483: 0.96% estimated exploitation activity in the next 30 days; percentile 61.72 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

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

Published by the source

2 Mar 2023, 23:12 UTC

Last modified by the source

20 May 2024, 21:49 UTC

Source last checked

26 Oct 2026, 15:04 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-6gc3-crp7-25w5

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# Patch Next advisory brief: CVE-2023-26483

Advisory: gosaml2 vulnerable to Denial Of Service Via Deflate Decompression Bomb
IDs: CVE-2023-26483, GHSA-6gc3-crp7-25w5
Record: https://patchnext.com/advisories/cve-2023-26483 (revision 1, source checked 26 Oct 2026, 15:04 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 5.3)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/russellhaering/gosaml2 0.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/russellhaering/gosaml2: affected < 0.9.0; fixed in 0.9.0

## Suggested inspection (read-only)
- Go github.com/russellhaering/gosaml2: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/russellhaering/gosaml2.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-6gc3-crp7-25w5 (GitHub-reviewed advisory GHSA-6gc3-crp7-25w5 lists affected ranges: Go github.com/russellhaering/gosaml2 >=0 <0.9.0)

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