TI-2026-04247 Aliases CVE-2026-4873 GHSA-5fgw-rv54-prjx

connection reuse ignores TLS requirement

LOW 26CWE-319Published 2026-05-13 · Updated 2026-09-15

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: High
Impact type: Information disclosure, Spoofing
Confidentiality · integrity · availability: High · None · None
Fix status: Partial Red Hat: 1 fixed, 13 without a fix

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and Red Hat. Impact type from CWE-319 and CWE-295.

Summary

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.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00329 26th percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix Partial curl (curl): 8.14.2, 8.16.1, 8.20.0Red Hat: 1 advisoryRed Hat: 1 fixed, 13 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: No
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
curl	curl	7.20.0 to before 8.14.2; 8.15.0 to before 8.16.1; 8.17.0 to before 8.20.0	8.14.2, 8.16.1, 8.20.0	Patch available	CNA
curl	curl	8.19.0; 8.18.0; 8.17.0; 8.16.0; 8.15.0; 8.14.1; 8.14.0; 8.13.0; 8.12.1; 8.12.0; 8.11.1; 8.11.0; 8.10.1; 8.10.0; 8.9.1; 8.9.0; 8.8.0; 8.7.1; 8.7.0; 8.6.0; 8.5.0; 8.4.0; 8.3.0; 8.2.1; 8.2.0; 8.1.2; 8.1.1; 8.1.0; 8.0.1; 8.0.0; 7.88.1; 7.88.0; 7.87.0; 7.86.0; 7.85.0; 7.84.0; 7.83.1; 7.83.0; 7.82.0; 7.81.0; 7.80.0; 7.79.1; 7.79.0; 7.78.0; 7.77.0; 7.76.1; 7.76.0; 7.75.0; 7.74.0; 7.73.0; 7.72.0; 7.71.1; 7.71.0; 7.70.0; 7.69.1; 7.69.0; 7.68.0; 7.67.0; 7.66.0; 7.65.3; 7.65.2; 7.65.1; 7.65.0; 7.64.1; 7.64.0; 7.63.0; 7.62.0; 7.61.1; 7.61.0; 7.60.0; 7.59.0; 7.58.0; 7.57.0; 7.56.1; 7.56.0; 7.55.1; 7.55.0; 7.54.1; 7.54.0; 7.53.1; 7.53.0; 7.52.1; 7.52.0; 7.51.0; 7.50.3; 7.50.2; 7.50.1; 7.50.0; 7.49.1; 7.49.0; 7.48.0; 7.47.1; 7.47.0; 7.46.0; 7.45.0; 7.44.0; 7.43.0; 7.42.1; 7.42.0; 7.41.0; 7.40.0; 7.39.0; 7.38.0; 7.37.1; 7.37.0; 7.36.0; 7.35.0; 7.34.0; 7.33.0; 7.32.0; 7.31.0; 7.30.0; 7.29.0; 7.28.1; 7.28.0; 7.27.0; 7.26.0; 7.25.0; 7.24.0; 7.23.1; 7.23.0; 7.22.0; 7.21.7; 7.21.6; 7.21.5; 7.21.4; 7.21.3; 7.21.2; 7.21.1; 7.21.0; 7.20.1; 7.20.0	—	No fix listed	CNA

curl Vendorcurl Affected 7.20.0 to before 8.14.2; 8.15.0 to before 8.16.1; 8.17.0 to before 8.20.0 Fixed in 8.14.2, 8.16.1, 8.20.0 Patch available CNA
curl Vendorcurl Affected 8.19.0; 8.18.0; 8.17.0; 8.16.0; 8.15.0; 8.14.1; 8.14.0; 8.13.0; 8.12.1; 8.12.0; 8.11.1; 8.11.0; 8.10.1; 8.10.0; 8.9.1; 8.9.0; 8.8.0; 8.7.1; 8.7.0; 8.6.0; 8.5.0; 8.4.0; 8.3.0; 8.2.1; 8.2.0; 8.1.2; 8.1.1; 8.1.0; 8.0.1; 8.0.0; 7.88.1; 7.88.0; 7.87.0; 7.86.0; 7.85.0; 7.84.0; 7.83.1; 7.83.0; 7.82.0; 7.81.0; 7.80.0; 7.79.1; 7.79.0; 7.78.0; 7.77.0; 7.76.1; 7.76.0; 7.75.0; 7.74.0; 7.73.0; 7.72.0; 7.71.1; 7.71.0; 7.70.0; 7.69.1; 7.69.0; 7.68.0; 7.67.0; 7.66.0; 7.65.3; 7.65.2; 7.65.1; 7.65.0; 7.64.1; 7.64.0; 7.63.0; 7.62.0; 7.61.1; 7.61.0; 7.60.0; 7.59.0; 7.58.0; 7.57.0; 7.56.1; 7.56.0; 7.55.1; 7.55.0; 7.54.1; 7.54.0; 7.53.1; 7.53.0; 7.52.1; 7.52.0; 7.51.0; 7.50.3; 7.50.2; 7.50.1; 7.50.0; 7.49.1; 7.49.0; 7.48.0; 7.47.1; 7.47.0; 7.46.0; 7.45.0; 7.44.0; 7.43.0; 7.42.1; 7.42.0; 7.41.0; 7.40.0; 7.39.0; 7.38.0; 7.37.1; 7.37.0; 7.36.0; 7.35.0; 7.34.0; 7.33.0; 7.32.0; 7.31.0; 7.30.0; 7.29.0; 7.28.1; 7.28.0; 7.27.0; 7.26.0; 7.25.0; 7.24.0; 7.23.1; 7.23.0; 7.22.0; 7.21.7; 7.21.6; 7.21.5; 7.21.4; 7.21.3; 7.21.2; 7.21.1; 7.21.0; 7.20.1; 7.20.0 Fixed in — No fix listed CNA

CPE configurations NVD · 1

CPE	Versions	Role	Vendor
cpe:2.3:a:haxx:curl::::::::	7.20.0 to before 8.20.0	Vulnerable	Haxx

cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:* Versions 7.20.0 to before 8.20.0 Vulnerable ·Haxx

Remediation

Fix · CNA curl (curl) Fixed in 8.14.2, 8.16.1, 8.20.0

Red Hat 1 advisory

RHSA-2026:12916 Released 2026-05-02 · Red Hat rating Moderate
Red Hat Hardened Images RPMs bug fix and enhancement update
- Red Hat Hardened Images curl-8.20.0-0.1.hum1@aarch64, curl-8.20.0-0.1.hum1@src, curl-8.20.0-0.1.hum1@x86_64 +6

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

Release · 2026-05-13
curl 8.14.2, 8.16.1, 8.20.0
7 records Highest priority Priority HIGH 2 HIGH, 2 MEDIUM, 3 LOW
Other records, highest priority first
- TI-2026-05503 stale custom cookie host causes cookie leakPriority HIGH 72
- TI-2026-05056 wrong reuse of SMB connectionPriority HIGH 72
- TI-2026-06291 cross-proxy Digest auth state leakPriority MEDIUM 63
Show all 7 records →

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

Product	Status	Plan or fix
Confidential Compute Attestation	Affected	No fix yet: Fix deferred
Logging Subsystem for Red Hat OpenShift	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 10	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 6	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 7	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 8	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux 9	Affected	No fix yet: Fix deferred
Red Hat Enterprise Linux AI (RHEL AI) 3	Affected	No fix yet: Fix deferred
Red Hat JBoss Core Services	Affected	No fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)	Affected	—
Red Hat OpenShift Container Platform 4	Affected	No fix yet: Fix deferred
Red Hat OpenShift Dev Spaces	Affected	No fix yet: Fix deferred
Red Hat Trusted Profile Analyzer	Affected	No fix yet: Fix deferred
Red Hat Hardened Images	Fixed	RHSA-2026:12916

Not affected: 2 products

Red Hat Hardened Images
Red Hat OpenShift AI (RHOAI)

Timeline

2026-10-02 Threatist record created from CVE-2026-4873
2026-10-03 Alias added: GHSA-5fgw-rv54-prjx
2026-11-06 Affected versions changed · Red Hat

References

Exploit 1

https://hackerone.com/reports/3621851

Patch 2

Advisory 1

https://curl.se/docs/CVE-2026-4873.json

TI-2023-19922 Out-of-bounds write in curl CVSS 3.1CRITICAL 9.8
TI-2026-16162 Negotiate ambient user conn reuse CVSS 3.1CRITICAL 9.8
TI-2026-10231 cross-origin Digest auth state leak CVSS 3.1CRITICAL 9.8
TI-2026-09063 HTTP/2 stream-dependency tree UAF CVSS 3.1CRITICAL 9.8
TI-2026-07976 stale proxy password leak CVSS 3.1CRITICAL 9.8
TI-2026-07845 SASL double-free CVSS 3.1CRITICAL 9.8

See all 103 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences