Cyber Resilience

CVE-2026-8924

Info Disclosure in Haxx Curl 7.46.0 – 8.21.0

Public PoCInfo Disclosure
Published
03 July 2026
Modified
15 September 2026
Patch / advisory
View advisory
CVSS Score v3.1 9.1
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS Score 0.0066 50th percentile
Risk Priority 68 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-8924 is a critical-severity Insertion of Sensitive Information Into Sent Data (CWE-201) vulnerability in Haxx Curl. Its CVSS base score is 9.1 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Network Sniffing (T1040); ranked at the 50th 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 AC-3 (Access Enforcement) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

A flaw in curl’s cookie parsing logic allows a malicious HTTP server to set "super cookies" that bypass the Public Suffix List check. This enables an attacker-controlled origin to inject cookies that curl subsequently scopes and transmits to unrelated third-party…

more

domains.

CWE(s)
CWE-201NVD-CWE-noinfo

Related Threats

MITRE ATT&CK Enterprise Techniques

T1040 Network Sniffing Credential Access
Adversaries may passively sniff network traffic to capture information about an environment, including authentication material passed over the network.
attack.mitre.org →
T1557 Adversary-in-the-Middle Credential Access
Adversaries may attempt to position themselves between two or more networked devices using an adversary-in-the-middle (AiTM) technique to support follow-on behaviors such as [Network Sniffing](https://attack.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2026-82209Same product: Haxx Curl
CVE-2025-10966Same product: Haxx Curl
CVE-2026-4873Same product: Haxx Curl
CVE-2026-6276Same product: Haxx Curl
CVE-2025-15224Same product: Haxx Curl
CVE-2025-5025Same product: Haxx Curl
CVE-2026-11856Same product: Haxx Curl
CVE-2026-7168Same product: Haxx Curl
CVE-2026-8286Same product: Haxx Curl
CVE-2025-14819Same product: Haxx Curl

Affected Assets

haxx
curl
7.46.0 — 8.21.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 1 hardening rule · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)
  • V14.2.3

Mitigating Controls (NIST 800-53 r5) AI

AC-3 Access Enforcement partial match

Enforces authorizations on logical access so that sensitive data is not released to unauthorized recipients.

AC-4 Information Flow Enforcement partial match

Directly enforces policy-based information flow rules that block transmission of sensitive data to unauthorized actors.

SI-15 Information Output Filtering partial match

Requires validation of outbound information to ensure sensitive content is not disclosed in responses or messages.

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.

DE.CM-09 partial match
prevents

Monitoring runtime data flows and outputs can detect sensitive data being transmitted.

PR.DS-02 partial match
prevents

Protecting data-in-transit can include filtering or encrypting to avoid exposing sensitive content.

PR.DS-10 partial match
prevents

Protecting data-in-use includes removing confidential values before they are processed or sent.

PR.PS-06 partial match
prevents

Secure SDLC practices directly prevent insertion of sensitive data into application outputs and messages.

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.5.12 Classification of information partial match
mitigates

Classification identifies sensitive data so it is not inadvertently transmitted.

A.5.13 Labelling of information partial match
mitigates

Labelling makes sensitive data visible to developers and prevents accidental inclusion in outbound messages.

A.5.14 Information transfer partial match
mitigates

Information-transfer rules directly govern what data may be sent to external parties.

A.5.34 Privacy and protection of PII partial match
mitigates

PII-protection requirements reduce the chance of sending personal data to unauthorized recipients.

A.8.11 Data masking partial match
prevents

Data-masking techniques can prevent sensitive values from appearing in transmitted payloads.

A.8.12 Data leakage prevention partial match
mitigates

DLP controls inspect and block outbound flows that contain sensitive information.

References