Security Resilience

CVE-2023-39456

Fedoraproject Fedora 37 … 38

High EPSS
Published
17 October 2023
Modified
12 June 2025
Patch / advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.61 99.1th percentile
Risk Priority 80 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-39456 is a high-severity Improper Input Validation (CWE-20) vulnerability in Fedoraproject Fedora. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 0.9% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2023-39456 is an improper input validation vulnerability, tracked under CWE-20, that resides in Apache Traffic Server when processing malformed HTTP/2 frames. It affects versions 9.0.0 through 9.2.2 and carries a CVSS 3.1 base score of 7.5 reflecting network attackability without authentication or user interaction and a high impact on availability.

An unauthenticated remote attacker can send crafted HTTP/2 frames to trigger the flaw, resulting in a denial-of-service condition that disrupts service availability while leaving confidentiality and integrity unaffected.

Advisories from the Apache project and downstream distributions such as Fedora and Debian state that users should upgrade to version 9.2.3, which contains the fix; corresponding packages have been published in those repositories.

The associated EPSS score has remained flat at 0.0782 with no material increase since disclosure.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Improper Input Validation vulnerability in Apache Traffic Server with malformed HTTP/2 frames.This issue affects Apache Traffic Server: from 9.0.0 through 9.2.2. Users are recommended to upgrade to version 9.2.3, which fixes the issue.

CWE(s)

Related Threats

CVEs Like This One

CVE-2023-41752Same product: Apache Traffic Server
CVE-2023-30631Same product: Apache Traffic Server
CVE-2024-31309Same product: Apache Traffic Server
CVE-2024-38311Same product: Apache Traffic Server
CVE-2024-35296Same product: Apache Traffic Server
CVE-2026-33267Same product: Apache Traffic Server
CVE-2026-58186Same product: Apache Traffic Server
CVE-2024-38479Same product: Apache Traffic Server
CVE-2026-58183Same product: Apache Traffic Server
CVE-2024-24549Same product: Fedoraproject Fedora

Affected Assets

apache
traffic server
9.0.0 — 9.2.3
fedoraproject
fedora
37, 38

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-20

Security testing and developer training directly verify and enforce proper input validation, reducing exploitability of injection and malformed-data weaknesses.

addresses: CWE-20

Security testing and evaluation at multiple SDLC stages directly detects missing or flawed input validation, with the required remediation process ensuring fixes are applied.

addresses: CWE-20

Directly implements checks on information inputs to reject invalid data before processing.

addresses: CWE-20

Spam protection mechanisms perform filtering and detection on inbound/outbound messages, directly compensating for missing or weak input validation of unsolicited content.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

blocks

A.8.25 mandates security requirements, secure coding guidelines, checkpoints, testing (incl. code scans) and developer training in the SDLC, which reaches a slice of input validation defects but leaves the majority (incomplete enforcement, second-order inputs, parser differentials, post-validation canonicalization) unaddressed as in the SA-3 and A.8.28 anchors.

blocks

Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.

blocks

Security-by-design principles explicitly call for data validation and sanitization at every layer, reducing the chance that malformed or malicious input will be processed without scrutiny.

prevents

Requiring language-specific secure coding standards, peer review, SAST and documented mitigation of common programming errors forces validation of all inputs before they are trusted.

finds

Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-20, a class-level weakness, and none of its children carries one either.

References