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curl SASL double-free

IdentifiersCVE-2026-8925CWE-415

CVE-2026-8925 is a medium-severity double-free vulnerability in curl/libcurl's SASL authentication handling when curl is built with libgsasl. In SASL-enabled protocol flows, curl's logic can clean up the GSASL context twice without clearing the pointer between cleanup operations, resulting in free() being called twice on the same pointer. The issue affects SASL-capable protocols including IMAP, POP3, and SMTP, and is reachable via both the curl command-line tool and libcurl integrations. According to the provided content, the flaw was introduced by commit ab650379a8c25ca952f6 and affects curl versions 8.15.0 through 8.20.0 inclusive.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful triggering causes memory corruption conditions consistent with a double-free, which can lead to process crashes and potentially limited exploitation scenarios. The project assessed attacker control over the second free as difficult, but noted that server behavior can influence the sequence and timing sufficiently that malicious exploitation could not be ruled out. Practical impact is therefore primarily denial of service, with some risk of memory-corruption-based exploitation depending on allocator behavior and runtime conditions.

Mitigation

If you can’t patch tonight, do this now.

As a workaround, avoid using SASL-dependent protocols and flows affected by this bug, specifically IMAP, POP3, and SMTP, on builds linked with libgsasl. Reducing or disabling exposure to those protocol paths limits reachability until patched binaries can be deployed.

Remediation

Patch, then assume compromise.

Upgrade to curl 8.21.0 or later, which contains the fix for CVE-2026-8925. If immediate upgrade is not possible, apply the upstream patch locally. The provided content states the issue was fixed by commit 3da249e1f0716c06644ed3522.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

ACTIVITY FEED

Recent activity

7 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

7 SOURCESView more in app

security affairsNews

Jun 25, 2026

Curl Fixes a 25-Year-Old Bug in Its Largest CVE Release Yet - Security Affairs

A double-free vulnerability in curl's SASL authentication handling where the same GSASL context could be freed twice in SASL-enabled protocol flows.

cyber security newsNews

Jun 25, 2026

25-Year-Old Vulnerability in curl Used by 30 Billion Devices Finally Patched

A double-free vulnerability in curl/libcurl SASL authentication flows involving the GSASL context, potentially leading to memory corruption or crashes.

security weekNews

Jun 25, 2026

25-Year-Old Vulnerability Patched in Curl - SecurityWeek

A curl/libcurl double-free vulnerability.

daniel haxx seNews

Jun 24, 2026

curl 8.21.0 | daniel.haxx.se

A medium-severity curl/libcurl vulnerability involving a double-free condition in SASL handling.

+2 more in the timeline

What this page doesn’t show

The version that knows your environment.

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity1

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-8925

NVD

nvd.nist.gov/vuln/detail/CVE-2026-8925

MITRE CWE · CWE-415

cwe.mitre.org