dbcve.org
CurlApplication · Haxx

CVE-2026-8925

CRITICAL · 9.8 CVSS v3.1 Published 2026-07-03
Fix available
A fix is available. Upgrade to 8.21.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click Patch available 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
The curl logic that works with SASL authentication could end up cleaning up the GSASL context *twice* without clearing the pointer in between, making it `free()` the same pointer twice.

In the news

Third-party coverage
Trending covered by 2 outlets this week · latest 2mo ago

Surfaced from public web coverage — external links open in a new tab.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

A double-free vulnerability exists in curl's SASL authentication logic where the GSASL context is cleaned up twice without clearing the pointer between cleanups, causing the same memory pointer to be freed twice.

MitigationUpdate curl to the patched version that properly clears the GSASL context pointer after the first cleanup to prevent double-free. If immediate patching is not possible, consider disabling or restricting SASL authentication mechanisms in affected services as a temporary workaround.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
CurlApplication
Affected:>= 8.15.0, < 8.21.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Find installed curl version
    Run 'curl --version' and note the version number in the output
    Affected if The version shown is >= 8.15.0 and < 8.21.0
  2. Confirm GSASL library presence
    Check if libgsasl is installed on the system (e.g., 'dpkg -l libgsasl' or 'rpm -qa | grep gsasl')
    Affected if GSASL libraries are installed and curl was built with SASL support
  3. Check if curl was built with SASL support
    Run 'curl -V' and look for 'GSSAPI' or 'SASL' in the features list
    Affected if GSSAPI or SASL support is compiled into curl
  4. Identify active SASL authentication usage
    Review application configs or command lines that invoke curl for SASL-based authentication (IMAP, SMTP, LDAP, HTTP with Negotiate/NTLM)
    Affected if The curl installation is being used with SASL authentication mechanisms in any service or script

A user is affected if their installed curl version falls within 8.15.0 to 8.20.x AND the curl binary includes SASL/GSSAPI support AND is actively using SASL authentication, as the double-free only triggers when the GSASL context is cleaned up during SASL operations.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 8.21.0 or later
Fixed in 8.21.0
Vendor patch curl.se →
Interim mitigation

Update curl to the patched version that properly clears the GSASL context pointer after the first cleanup to prevent double-free. If immediate patching is not possible, consider disabling or restricting SASL authentication mechanisms in affected services as a temporary workaround.

Recommended fix High confidence

8.21.0 or later

  1. Check current curl version by running: curl --version
  2. If the version is >= 8.15.0 and < 8.21.0, the system is vulnerable to this double-free vulnerability
  3. Upgrade curl to version 8.21.0 or later using your system's package manager (e.g., apt-get update && apt-get upgrade curl, yum update curl, or brew upgrade curl)
  4. Verify the upgrade was successful by running curl --version again and confirming the version is 8.21.0 or higher
  5. If curl is bundled with another application, update that application to a version that includes the fixed curl library

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Curl Scoped from the published advisory
  • Consultation3.0 h
  • Implementation4.0 h
  • Testing5.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,610
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,176.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-8925 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data