CVE-2023-26483

gosaml2 vulnerable to Denial of Service via deflate decompression bomb

MEDIUM
5.3
CVSS Score
Published: March 3, 2023 at 10:02 PM UTC
Updated: June 17, 2026 at 05:43 AM UTC
2 products affected across 2 vendorsGOSAML2Project GOSAML2

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Severity
MEDIUM5.3
Exploit prediction
EPSS 1.0%
SSVC
No known exploit

Description

gosaml2 is a Pure Go implementation of SAML 2.0. 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. 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. This issue is fixed in version 0.9.0.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 0.9.0
Affected range stops below 0.9.0, so it looks safe — our inference, not a vendor statement
v < 0.9.0
Affected range stops below 0.9.0, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.3MEDIUMGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-409NVD-CWE-Other

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