SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-41524

While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request processing, allowing an external source to DoS the server.

HIGH 7.5EPSS 25.2%

Does this matter?

EPSS puts the probability of exploitation in the next 30 days at 25.2%, higher than 98% of all known CVEs. Patch or mitigate before the next change window.

Description

While fuzzing the 2.4.49 httpd, a new null pointer dereference was detected during HTTP/2 request processing, allowing an external source to DoS the server. This requires a specially crafted request. The vulnerability was recently introduced in version 2.4.49. No exploit is known to the project.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
25.17% probability · 98th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-476
Affected
apache/http server · fedoraproject/fedora · oracle/instantis enterprisetrack · netapp/cloud backup
Source
security@apache.org
EPSS trend
0%15%30%3 November 2026: 25.17%3 November 20263 November 2026

EPSS 25.2% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.