CVE-2023-44487

IETF HTTP/2: Rapid Reset Attack

As of , CVE-2023-44487 in IETF HTTP/2 is on CISA's list of exploited vulnerabilities: CISA listed it on . Our patch-first group: Patch this week.

Exploited
Yes: CISA listed it on 10 October 2023
US federal deadline
31 October 202321 days after CISA listed it. US federal civilian agencies must fix it by then.
Used in ransomware campaigns
Not known to CISA
EPSS score
0.99Higher than 99% of the CVEs EPSS scores. EPSS estimates the chance of exploitation activity in the next 30 days.
EPSS when listed
No score that dayThe EPSS file of the day CISA listed it has no score for it.
Public exploit
1 Exploit-DB entry
Fix
Vendor advice: blog.cloudflare.comLinks below, from CISA's entry.

What CISA says to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

CISA's required action

What the flaw is

HTTP/2 contains a rapid reset vulnerability that allows for a distributed denial-of-service attack (DDoS).

CISA's description

The HTTP/2 protocol allows a denial of service (server resource consumption) because request cancellation can reset many streams quickly, as exploited in the wild in August through October 2023.

The CVE record's description, from mitre

CVE published
10 October 2023
Assigned by
mitre
CVSS
7.5 High (CVSS 3.1, from CISA-ADP)
CWE-400
Uncontrolled Resource Consumption
CISA SSVC, exploitation
active
CISA SSVC, automatable
yes
CISA SSVC, technical impact
partial

Timeline

  1. The CVE record was published.
  2. CISA added it to its list of exploited vulnerabilities.
  3. The US federal deadline to fix it.
  4. CISA changed its entry. Edited: notes and required action.
  5. Exploit-DB published an exploit (EDB-ID 52426).

Public exploits

Facts from Metasploit's module list and Exploit-DB's index; we never copy exploit code.

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