CVE-2021-21299

Exploitation

Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.

SSVC decision

Not assessed by CISA

EPSS probability

4.73% probability of exploitation activity in the next 30 days.

EPSS percentile

Equal to or higher than the score of 91.5% of scored records. A rank, not a probability.

NVD base score

8.1 (CVSS v3.x), scored by the NVD independently of the CNA.

NVD CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

NVD analysis status

Modified. NVD last modified this record on 2026-06-17.

Red Hat severity

No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

Published

2021-02-11 18:00Z5 YR AGO

Last updated

2024-08-03 18:09Z2 YR AGO

Reserved

2020-12-22

Assigning CNA

GitHub_M

Record state

PUBLISHED

Severity

Medium (CVSS 4.8)

CNA CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

Weaknesses

• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')Base

Data version

5.1

Document digest

b8aa1a52b867d3672b8ceb0a98e228553ae78a7176d04a298acf44ddf3e36cfe

• portswigger.nethttps://portswigger.net/research/http-desync-attacks-request-smuggling-rebornx_refsource_MISC
• rustsec.orghttps://rustsec.org/advisories/RUSTSEC-2021-0020.htmlx_refsource_MISC
• github.comhttps://github.com/hyperium/hyper/security/advisories/GHSA-6hfq-h8hq-87mfx_refsource_CONFIRM
• crates.iohttps://crates.io/crates/hyperx_refsource_MISC
• github.comhttps://github.com/hyperium/hyper/commit/8f93123efef5c1361086688fe4f34c83c89cec02x_refsource_MISC