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Weekly Signal
Live intelligence Updated 19 Aug 2026 · 20:27 UTC

Akka, Amazon, Apache +30 more · Http Server, Opensearch Data Prepper, APISIX +162 more

CVE-2023-44487

HTTP/2 Rapid Reset Attack Vulnerability

Recommended action

Validate affected assets and exposure now, then remediate on an accelerated schedule. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

View response plan
CVSS7.5
EPSS100.0%
KEVYes
ExploitationConfirmed exploitation
PatchPatch or guidance available ↓

Assessment

Why it matters

CISA lists this vulnerability as known to be exploited; exploitation is confirmed; EPSS is 100.0%; technical severity is CVSS 7.5.

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.

Who should care

  • Teams operating Http Server, Opensearch Data Prepper, APISIX +162 more
  • Vulnerability and exposure management teams
  • Security operations teams monitoring exploitation activity

Response plan

What I would do

  1. Confirm whether Http Server, Opensearch Data Prepper, APISIX +162 more is present in the environment.
  2. Identify affected versions and establish whether vulnerable services are exposed or reachable.
  3. Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
  4. Review relevant security telemetry for evidence of attempted or successful exploitation.
  5. Document the remediation decision and track it to verified completion.

Vendor remediation

Patch and remediation links

Use the vendor source below to confirm the correct fixed version, package or mitigation for your affected product.

Technical details

CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE
CWE-400
Affected versions
Akka Http Server (End Excluding: 10.5.3); Amazon Opensearch Data Prepper (End Excluding: 2.5.0); Apache APISIX (End Excluding: 3.6.1); Apache Solr (End Excluding: 9.4.0); Apache Tomcat (Version: 11.0.0); Apache Traffic Server (Start Including: 9.0.0, End Excluding: 9.2.3); Apple Swiftnio Http/2 (End Excluding: 1.28.0); Caddyserver Caddy (End Excluding: 2.7.5)
Published
10 October 2023
Attack vector
Network
Privileges required
None
User interaction
None

Signal timeline

  1. CVE published
  2. Added to CISA KEV
  3. Latest EPSS score: 100.0%
  4. Signal calculated at 83

External references

Live public intelligence This assessment combines public-source evidence. Validate the affected product, version and exposure against your own environment before making a risk decision.