Cyber Resilience

CVE-2026-33487

Goxmldsig Project Goxmldsig ≤ 1.6.0

Public PoC
Published
26 March 2026
Modified
10 August 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS Score 0.0030 22th percentile
Risk Priority 56 floored blend · peak EPSS

Summary

CVE-2026-33487 is a high-severity Improper Verification of Cryptographic Signature (CWE-347) vulnerability in Goxmldsig Project Goxmldsig. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Supply Chain Compromise (T1195); ranked at the 22th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SC-13 (Cryptographic Protection) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-33487 affects the goxmlsig Go library, which implements XML Digital Signatures, in versions prior to 1.6.0. The vulnerability resides in the `validateSignature` function within `validate.go`, where the code iterates through references in the `SignedInfo` block to match the signed element's ID. Due to a loop variable capture issue in Go versions before 1.22—or when using an older version in `go.mod`—the function takes the address of the loop variable `_ref` instead of its value. Consequently, if multiple references match the ID or the loop logic fails, the `ref` pointer always points to the last element in the `SignedInfo.References` slice. Published on 2026-03-26, the issue carries a CVSS v3.1 score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N) and maps to CWE-347 and CWE-682.

A remote, unauthenticated attacker can exploit this vulnerability with low complexity and no user interaction by supplying a malicious XML document containing multiple references in `SignedInfo` that match the target element's ID. This causes the validation to reference the incorrect (last) element, enabling signature validation bypass and high integrity impact, such as accepting forged or altered XML signatures in applications relying on goxmlsig for verification.

goxmlsig version 1.6.0 includes a patch addressing this flaw. Additional details on the vulnerability and remediation are available in the GitHub security advisory at https://github.com/russellhaering/goxmldsig/security/advisories/GHSA-479m-364c-43vc.

OWASP Top 10 for Web (2025)

A04:2025 Cryptographic Failures

EU & UK References

Vulnerability Data

goxmlsig provides XML Digital Signatures implemented in Go. Prior to version 1.6.0, the `validateSignature` function in `validate.go` goes through the references in the `SignedInfo` block to find one that matches the signed element's ID. In Go versions before 1.22, or…

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when `go.mod` uses an older version, there is a loop variable capture issue. The code takes the address of the loop variable `_ref` instead of its value. As a result, if more than one reference matches the ID or if the loop logic is incorrect, the `ref` pointer will always end up pointing to the last element in the `SignedInfo.References` slice after the loop. goxmlsig version 1.6.0 contains a patch.

CWE(s)
CWE-347CWE-682

Related Threats

MITRE ATT&CK Enterprise Techniques

T1195 Supply Chain Compromise Initial Access
Adversaries may manipulate products or product delivery mechanisms prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1195.002 Compromise Software Supply Chain Initial Access
Adversaries may manipulate application software prior to receipt by a final consumer for the purpose of data or system compromise.
attack.mitre.org →
T1542 Pre-OS Boot Stealth
Adversaries may abuse Pre-OS Boot mechanisms as a way to establish persistence on a system.
attack.mitre.org →
T1553 Subvert Trust Controls Defense Impairment
Adversaries may undermine security controls that will either warn users of untrusted activity or prevent execution of untrusted programs.
attack.mitre.org →
T1553.002 Code Signing Defense Impairment
Adversaries may create, acquire, or steal code signing materials to sign their malware or tools.
attack.mitre.org →
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-39829Shared CWE-347
CVE-2026-1237Shared CWE-347
CVE-2026-47201Shared CWE-347
CVE-2026-6328Shared CWE-347
CVE-2026-33894Shared CWE-347
CVE-2026-5050Shared CWE-347
CVE-2026-48558Shared CWE-347
CVE-2026-23967Shared CWE-347
CVE-2025-43023Shared CWE-347
CVE-2024-23480Shared CWE-347

Affected Assets

goxmldsig project
goxmldsig
≤ 1.6.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 14 hardening rules · 5 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V15.2.2

Mitigating Controls (NIST 800-53 r5) AI

SA-11 Developer Testing and Evaluation good match

Developer testing and evaluation directly exercises calculations and can discover incorrect or unintended results used in security decisions.

SC-13 Cryptographic Protection good match

Requiring cryptographic protection mechanisms forces correct signature verification to be implemented for data protection.

SI-7 Software, Firmware, and Information Integrity good match

Mandating integrity verification tools directly requires proper cryptographic signature checking to detect unauthorized changes.

SA-15 Development Process, Standards, and Tools partial match

Requiring documented development processes and standards can enforce coding rules and tool usage that reduce introduction of calculation errors.

SA-8 Security and Privacy Engineering Principles partial match

Engineering principles applied during design and implementation can require verified algorithms and safe arithmetic that structurally avoid incorrect calculation results.

SC-23 Session Authenticity partial match

Protecting session authenticity requires correct verification of cryptographic signatures or equivalent mechanisms.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.DS-01 mostly match
prevents

Digital signatures are explicitly cited to protect integrity of data-at-rest, so proper verification directly mitigates the weakness.

PR.DS-02 mostly match
prevents

Digital signatures are explicitly cited to protect integrity of data-in-transit, so proper verification directly mitigates the weakness.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly prevent incorrect calculations via reviews, testing, and verification in security-critical code.

ID.RA-09 partial match
prevents

Requires assessing authenticity and integrity of acquired assets, which commonly relies on signature verification but is limited to pre-acquisition.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
finds

Security testing in development and acceptance can detect calculation flaws before deployment.

A.8.24 Use of cryptography partial match
prevents

Establishing approved cryptographic solutions and usage practices lowers the probability that signature-verification steps will be omitted or incorrectly implemented.

A.8.25 Secure development life cycle partial match
prevents

Secure development lifecycle mandates verification steps that catch incorrect calculations before they reach production.

A.8.26 Application security requirements partial match
prevents

Application security requirements can explicitly call for numeric accuracy and bounds checking.

A.8.27 Secure system architecture and engineering principles partial match
degrades

Secure architecture principles include input validation and safe arithmetic design that reduce calculation errors.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly prohibit unsafe arithmetic and require defensive checks against incorrect results.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-347
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-347
Oracle Linux 9 (2 rules)
  • V-271525 OL 9 must have GPG signature verification enabled for all software repositories. prevents CWE-347
  • V-271523 OL 9 must check the GPG signature of locally installed software packages before installation. prevents CWE-347
RHEL 7 (2 rules)
  • V-204447 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-347
  • V-204448 The Red Hat Enterprise Linux operating system must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-347
RHEL 8 (1 rule)
  • V-230264 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components from a repository without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-347
RHEL 9 (1 rule)
  • V-257822 RHEL 9 must have GPG signature verification enabled for all software repositories. prevents CWE-347

References