CVE-2026-18924: curl Use After Free

CVSS: 9.1v3.1CriticalModified

AliasesALPINE-CVE-2026-18924UBUNTU-CVE-2026-18924DEBIAN-CVE-2026-18924+3 more

Published 06-09-2026Last modified 15-09-2026

Vulnerability summary

CVE-2026-18924 is a critical (CVSS 9.1) Use After Free vulnerability in curl. EPSS estimates a 0.58% chance of exploitation in the next 30 days, higher than 47.1% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk

70/100

0100

High · default modelHow is this calculated?

CVSS score

9.1/10

010

Critical · v3.1 (CVE.org)

EPSS score

0.58%

0%100%

Low · -0.31 pp in 30 days

KEVNot listedIn no KEV catalog

RansomwareNone recordedNo known use recorded

Public exploits1reference

Advisory lineage

Upstream 0 · Downstream 5 · Related 2

MGASA-2026-0515 OPENSUSE-SU-2026:11696-1 RHSA-2026:63161 RHSA-2026:63514 USN-8820-1

Timeline

06-09-2026
PublishedVulnerability first disclosed.
15-09-2026
Last modifiedVulnerability information updated.

Description

A flaw in libcurl's handling of HTTP/2 Server Push streams, when the parent handle is set to share connections with other handles, can lead to use-after-free in the cleanup process.

CVSS metrics

7 scores · 7 sources · 1 version

v3.19.1

EPSS trend

Probability

0.58%

Chance of exploitation in the next 30 days

Percentile

47%

Versus all other CVEs

30-day change

-0.31 pp

From 0.90% on 21-09-2026

21-09-202621-10-2026

EPSS score

0.58%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found

referenceUnverified
Exploit Reference (hackerone.com)
Maturity: unknown

Weaknesses

CWE · root cause

CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.

Affected systems

Chainguard2 products

curl< 8.22.0-r0
libcurl4All versions (No fix recorded)

Wolfi2 products

curl< 8.22.0-r0
libcurl4All versions (No fix recorded)

Alpine1 product

curl≥ 7.44.0, < 8.22.0-r0

Curl1 product

curl≥ 7.44.0, < 8.14.2 | ≥ 8.15.0, < 8.16.1 | ≥ 8.17.0, < 8.20.1 | ≥ 8.21.0, < 8.22.0 | ≥ ea7134ac874a66107e54ff93657ac565cf2ec4aa, < 90325ff0444cbdff368bda5d26d6405a0bb6ee43 | 8.21.0 | 8.20.0 | 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

Debian1 product

curlAll versions (No fix recorded) | < 8.22.0~rc2-1

Haxx1 product

curl≥ 7.44.0, < 8.22.0

Ubuntu1 product

curl< 7.47.0-1ubuntu2.19+esm20 | < 7.58.0-2ubuntu3.24+esm14 | < 7.68.0-1ubuntu2.25+esm9 | < 7.81.0-1ubuntu1.29 | < 8.5.0-2ubuntu10.15 | < 8.20.0-2ubuntu11 | < 8.18.0-1ubuntu2.7

7 vendors · 9 products