CVE-2020-7731Public exploitNetwork attack vector

Service crash via nil parent dereference

Published Apr 30, 2021 · Updated Sep 17, 2024

NULL pointer dereference in gosaml2 before 0.7.0 allows remote attackers to crash SAML-consuming services with malformed XML signatures. In validateAssertionSignatures, malformed assertion structure can leave an unverified Assertion without a parent, but the error path dereferences Parent().Tag. A network-reachable application must pass attacker-controlled SAML response data into RetrieveAssertionInfo; the resulting panic interrupts that process unless recovered.

CVSS severity7.5
High
EPSS probability1.66%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in gosaml2 before 0.7.0 allows remote attackers to crash SAML-consuming services with malformed XML signatures. In validateAssertionSignatures, malformed assertion structure can leave an unverified Assertion without a parent, but the error path dereferences Parent().Tag. A network-reachable application must pass attacker-controlled SAML response data into RetrieveAssertionInfo; the resulting panic interrupts that process unless recovered.

The record

CVE
CVE-2020-7731
Published
Apr 30, 2021
Updated
Sep 17, 2024
Vendor
Russell Haering
Product
gosaml2
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 30, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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  1. Affected versionversion=0 <unspecified

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Russell Haering · gosaml2version=0 <unspecified

Published CVSS scores

5.0NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5SnykCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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