CVE-2026-4873A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool.
Updated under an hour ago ()
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It affects haxx curl. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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A vulnerability exists where a connection requiring TLS incorrectly reuses an existing unencrypted connection from the same connection pool. If an initial transfer is made in clear-text (via IMAP, SMTP, or POP3), a subsequent request to that same host bypasses the TLS requirement and instead transmit data unencrypted.
- CVSS
- 5.9 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weakness (CWE)
- CWE-319, CWE-295
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Modified
- Record last updated
- Sep 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
haxx curl haxx:curl | from 7.20.0 before 8.20.0 | NVD |
References
- https://curl.se/docs/CVE-2026-4873.htmlpatch, vendor-advisory
- https://curl.se/docs/CVE-2026-4873.jsonvendor-advisory
- https://hackerone.com/reports/3621851exploit, issue-tracking, third-party-advisory
- http://www.openwall.com/lists/oss-security/2026/04/29/7mailing-list, patch, third-party-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.