Cyber Resilience

CVE-2026-40164

DoS

DoSCrypto Weakness
Published
14 April 2026
Modified
15 July 2026
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:N/A:H
EPSS Score 0.0037 29th percentile
Risk Priority 57 floored blend · peak EPSS

Summary

CVE-2026-40164 is a high-severity Use of Weak Hash (CWE-328) vulnerability in Redhat (inferred from references). Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique OS Credential Dumping (T1003); ranked at the 29th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to IA-5 (Authenticator Management) and SC-12 (Cryptographic Key Establishment and Management) — 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-2026-40164 is a hash collision vulnerability in jq, a command-line JSON processor. Prior to commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq employed MurmurHash3 with a hardcoded, publicly known seed value (0x432A9843) for JSON object hash table operations. This design flaw enabled attackers to precompute key collisions offline, causing all keys in a crafted JSON object to hash to the same bucket. As a result, hash table lookups degraded from average O(1) to O(n) performance, transforming typical jq expressions into O(n²) operations and leading to severe CPU exhaustion.

The vulnerability carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and is associated with CWE-328 (Reversible One-Way Hash) and CWE-407 (Inappropriate Time Handling, due to algorithmic complexity). Any remote attacker can exploit it without privileges or user interaction by providing a specially crafted JSON object of approximately 100 KB. Successful exploitation causes denial-of-service through resource exhaustion, impacting common jq deployments in CI/CD pipelines, web services, and data processing scripts; it is noted as more practical than prior heap overflow issues due to the small payload size.

The issue was addressed in jq commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, which patches the hash collision weakness. Security practitioners should update to this commit or later versions, as detailed in the GitHub security advisory (GHSA-wwj8-gxm6-jc29) and the patching commit.

OWASP Top 10 for Web (2025)

A04:2025 Cryptographic Failures

EU & UK References

Vulnerability Data

jq is a command-line JSON processor. Before commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq used MurmurHash3 with a hardcoded, publicly visible seed (0x432A9843) for all JSON object hash table operations, which allowed an attacker to precompute key collisions offline. By supplying a crafted JSON…

more

object (~100 KB) where all keys hashed to the same bucket, hash table lookups degraded from O(1) to O(n), turning any jq expression into an O(n²) operation and causing significant CPU exhaustion. This affected common jq use cases such as CI/CD pipelines, web services, and data processing scripts, and was far more practical to exploit than existing heap overflow issues since it required only a small payload. This issue has been patched in commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784.

CWE(s)
CWE-328CWE-407CWE-341

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003 OS Credential Dumping Credential Access
Adversaries may attempt to dump credentials to obtain account login and credential material, normally in the form of a hash or a clear text password.
attack.mitre.org →
T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
attack.mitre.org →
T1110.002 Password Cracking Credential Access
Adversaries may use password cracking to attempt to recover usable credentials, such as plaintext passwords, when credential material such as password hashes are obtained.
attack.mitre.org →
T1185 Browser Session Hijacking Collection
Adversaries may take advantage of security vulnerabilities and inherent functionality in browser software to change content, modify user-behaviors, and intercept information as part of various browser session hijacking techniques.
attack.mitre.org →
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
attack.mitre.org →
T1499.003 Application Exhaustion Flood Impact
Adversaries may target resource intensive features of applications to cause a denial of service (DoS), denying availability to those applications.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-41879Shared CWE-328
CVE-2025-27595Shared CWE-328
CVE-2026-48488Shared CWE-328
CVE-2024-23589Shared CWE-328
CVE-2025-59354Shared CWE-328
CVE-2025-49197Shared CWE-328
CVE-2025-47276Shared CWE-328
CVE-2025-21604Shared CWE-328
CVE-2025-9078Shared CWE-328
CVE-2026-21717Shared CWE-328

Affected Assets

Redhat
—
inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 5 OS baselines
Validate
Prove the fix (OWASP ASVS)
  • V11.2.3
  • V6.6.1
  • V6.5.2
  • V6.5.1

Mitigating Controls (NIST 800-53 r5) AI

SC-13 Cryptographic Protection good match

Mandating approved cryptographic algorithms and strengths directly stops selection of weak hash functions for integrity or other uses.

IA-5 Authenticator Management good match

Authenticator management requires generation and distribution of values that cannot be derived from observable state.

SC-12 Cryptographic Key Establishment and Management good match

Cryptographic key establishment mandates use of unpredictable, non-observable values for keys and nonces.

SC-23 Session Authenticity good match

Session authenticity protection requires session identifiers or tokens that resist prediction from network or timing observations.

SC-5 Denial-of-service Protection partial match

Denial-of-service protection directly reduces the impact of resource exhaustion triggered by worst-case algorithmic inputs.

SC-6 Resource Availability partial match

Resource availability allocation limits blast radius when an inefficient algorithm is forced into its worst case.

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.PS-06 full match
prevents

Secure-SDLC requirements explicitly forbid weak cryptographic algorithms, fully preventing CWE-328 while covering only one aspect of development practice.

PR.DS-01 mostly match
prevents

Proper data-at-rest integrity protection requires strong cryptographic hashes, directly blocking weak-hash usage.

PR.DS-02 mostly match
prevents

Data-in-transit integrity likewise depends on strong hashes, so the control prevents the weakness while the weakness only partially satisfies the outcome.

DE.CM-09 partial match
prevents

Runtime monitoring of software and resources can detect the performance impact of triggered worst-case complexity.

ID.RA-01 partial match
prevents

Identifying and recording algorithmic-complexity vulnerabilities directly addresses the root cause before exploitation.

PR.PS-01 partial match
prevents

Hardened configuration baselines can enforce use of cryptographically secure RNG sources and disable predictable state-based mechanisms.

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.8.24 Use of cryptography mostly match
prevents

Mandates use of approved cryptographic algorithms, directly preventing weak-hash selection.

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

Security testing can detect weak-hash usage but does not prescribe algorithm choice.

A.8.14 Redundancy of information processing facilities partial match
mitigates

Redundancy of processing facilities can absorb resource exhaustion from inefficient algorithms.

A.8.16 Monitoring activities partial match
finds

Monitoring activities can identify anomalous resource consumption indicative of algorithmic complexity attacks.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle includes design reviews that can catch inefficient algorithms before deployment.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify strong hashing, but the control is broader.

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).

Windows 10 (1 rule)
  • V-220937 The system must be configured to prevent the storage of the LAN Manager hash of passwords. prevents CWE-328
Windows 11 (1 rule)
  • V-253461 The system must be configured to prevent the storage of the LAN Manager hash of passwords. prevents CWE-328
Windows Server 2016 (1 rule)
  • V-225053 Windows Server 2016 must be configured to prevent the storage of the LAN Manager hash of passwords. prevents CWE-328
Windows Server 2019 (1 rule)
  • V-205654 Windows Server 2019 must be configured to prevent the storage of the LAN Manager hash of passwords. prevents CWE-328
Windows Server 2022 (1 rule)
  • V-254474 Windows Server 2022 must be configured to prevent the storage of the LAN Manager hash of passwords. prevents CWE-328

References