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🛡️ CVE-2026-5773 — curl

🟠 CVSS 7.5 — High ⚠️ Exploit Public CWE-918 NVD
7.5
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

libcurl might in some circumstances reuse the wrong connection for SMB(S)

transfers.

libcurl features a pool of recent connections so that subsequent requests can

reuse an existing connection to avoid overhead.

When reusing a connection a range of criteria must be met. Due to a logical

error in the code, a network transfer operation that was requested by an

application could wrongfully reuse an existing SMB connection to the same

server that was using a different 'share' than the new subsequent transfer

should.

This could in unlucky situations lead to the download of the wrong file or the

upload of a file to the wrong place. When this happens, the same credentials

are used and the server name is the same.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality high, integrity none, availability none.

CVSS metrics in full

The score comes from this vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

  • Attack vector: Network — reachable from anywhere that can route to the service.
  • Attack complexity: Low — the attack works reliably, with no preparation.
  • Privileges required: None — an unauthenticated stranger can try it.
  • User interaction: None — nobody has to be tricked into anything.
  • Scope: Unchanged — the damage stays inside the vulnerable component.
  • Confidentiality impact: High — total loss, or loss the attacker controls.
  • Integrity impact: None.
  • Availability impact: None.

Weakness class

CVE-2026-5773 is classified as CWE-918: Server-Side Request Forgery (SSRF). The server fetches a URL supplied by the caller, which can be pointed at internal systems it alone can reach.

Affected software

CVE-2026-5773 is recorded against 1 package.

  • curl (from 7.40.0 up to 8.20.0)

Timeline and source

Published on 13 May 2026 and last revised on 17 June 2026. A public exploit is known to exist, which raises the urgency of patching considerably. A vendor advisory or fix has been published. Record sourced from NVD.

References

curl.se
curl.se
hackerone.com
www.openwall.com
hackerone.com

Other advisories for this package

curl has other advisories on record. If you are patching this one, these are worth checking on the same host:

Same weakness in other software

These advisories are the same class of weakness (CWE-918: Server-Side Request Forgery (SSRF)) in other software:

Details

Severity HIGH
CVSS Score 7.5
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CWE CWE-918
Public Exploit ⚠️ Yes
Source NVD
Published 2026-05-13
Updated 2026-08-20
Modified 2026-06-17

Affected Packages

Software From version Fixed in
curl 7.40.0 8.20.0

References

Exploit, Issue Tracking, Third Party Advisory https://hackerone.com/reports/3650689
Mailing List, Patch, Third Party Advisory http://www.openwall.com/lists/oss-security/2026/04/29/9
Exploit, Issue Tracking, Third Party Advisory https://hackerone.com/reports/3650689

Exploit Protection

Are you running curl?

CVE-2026-5773 carries CVSS 7.5 High rating and a public exploit already exists. BotEraser checks your installation against this and other known CVE records, and blocks IPs associated with exploit activity.

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ⓘ Data Notice: The information presented above has been compiled from publicly available internet sources. Boteraser aggregates this data solely for informational purposes and does not independently classify, evaluate, or endorse any findings about the vulnerabilities listed. The accuracy and completeness of this information is the sole responsibility of the original publishers. Boteraser and its operators accept no liability for any decisions made based on this data.

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