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Mallory
MediumPublic exploit

curl OAuth2 Bearer Token Leak on Cross-Protocol Redirect

IdentifiersCVE-2025-14524CWE-522

CVE-2025-14524 is a credential leakage vulnerability in curl/libcurl. When an HTTP or HTTPS transfer uses an OAuth2 bearer token and follows a cross-protocol redirect to a second URL using the IMAP, LDAP, POP3, or SMTP scheme, curl may incorrectly forward the bearer token to the redirected target host. According to the provided content, the issue affects curl versions 7.33.0 through 8.17.0 and impacts both the curl command-line tool and applications using libcurl. The flaw is triggered in redirect-handling logic during protocol changes and can result in the Authorization bearer credential being sent over an unintended connection.

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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 exploitation can disclose an OAuth2 bearer token to an unintended remote host reached through the redirect chain. An attacker controlling or influencing the redirect target may obtain the leaked token and use it for unauthorized access to resources associated with that token. The primary impact is exposure of sensitive credentials rather than direct code execution or memory corruption.

Mitigation

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

If immediate patching is not possible, avoid using OAuth2 bearer tokens in curl transfers that may follow redirects. Disable automatic redirect following where feasible, and do not permit or strictly restrict cross-protocol redirects from HTTP(S) to IMAP, LDAP, POP3, or SMTP. Limit allowed redirect protocols and targets to trusted destinations only.

Remediation

Patch, then assume compromise.

Upgrade curl to version 8.18.0 or later, which contains the fix for this issue. For downstream products bundling curl, apply the vendor-provided security update that incorporates the corrected curl release or backported patch.
PUBLIC EXPLOITS

Exploits

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VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType
CurlCurlapplication
HaxxCurlapplication

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Exposure mapping

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Threat actor evidence

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Associated malware1

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Detection signatures

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Vendor-by-vendor mapping

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Social activity26

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