9.8

CVE-2023-40175: Inconsistent Interpretation of HTTP Requests in puma

Modified
AliasesSUSE-SU-2023:3957-1UBUNTU-CVE-2023-40175DEBIAN-CVE-2023-40175
Published 18-08-2023Last modified 07-10-2024

Vulnerability summary

CVE-2023-40175 is a critical (CVSS 9.8) vulnerability in puma. EPSS estimates a 0.85% chance of exploitation in the next 30 days, higher than 58.1% of scored vulnerabilities.

Priority
Prioritisesevere

Severe, CVSS 7.3 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)

Source freshness unavailable

How is this decided?
CVSS score
9.8/10
010
Critical · v3.1 (NVD)
EPSS score
0.85%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 4 · Related 3
RHSA-2024:0797SUSE-SU-2025:03466-1SUSE-SU-2025:03467-1USN-6682-1

Timeline

  1. 18-08-2023
    PublishedVulnerability first disclosed.
  2. 07-10-2024
    Last modifiedVulnerability information updated.

Description

Puma is a Ruby/Rack web server built for parallelism. Prior to versions 6.3.1 and 5.6.7, puma exhibited incorrect behavior when parsing chunked transfer encoding bodies and zero-length Content-Length headers in a way that allowed HTTP request smuggling. Severity of this issue is highly dependent on the nature of the web site using puma is. This could be caused by either incorrect parsing of trailing fields in chunked transfer encoding bodies or by parsing of blank/zero-length Content-Length headers. Both issues have been addressed and this vulnerability has been fixed in versions 6.3.1 and 5.6.7. Users are advised to upgrade. There are no known workarounds for this vulnerability.

CVSS metrics

5 scores · 5 sources · 1 version

EPSS trend

Probability

0.85%

Chance of exploitation in the next 30 days

Percentile

58%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.85% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Suse5 products
  • rubygem-puma&distro=SUSE Linux Enterprise High Availability Extension 15 SP1< 4.3.12-150000.3.12.1
  • rubygem-puma&distro=SUSE Linux Enterprise High Availability Extension 15 SP2< 4.3.12-150000.3.12.1
  • rubygem-puma&distro=SUSE Linux Enterprise High Availability Extension 15 SP3< 4.3.12-150000.3.12.1
  • rubygem-puma&distro=SUSE Linux Enterprise High Availability Extension 15 SP4< 4.3.12-150000.3.12.1
  • rubygem-puma&distro=SUSE Linux Enterprise High Availability Extension 15 SP5< 4.3.12-150000.3.12.1
Opensuse2 products
  • rubygem-puma&distro=openSUSE Leap 15.4< 4.3.12-150000.3.12.1
  • rubygem-puma&distro=openSUSE Leap 15.5< 4.3.12-150000.3.12.1
Debian1 product
  • puma< 5.6.5-3+deb12u1 | < 5.6.7-1
Puma1 product
  • puma< 5.6.7 | ≥ 6.0.0, < 6.3.1
RubyGems1 product
  • puma< 5.6.7 | ≥ 6.0.0, < 6.3.1
Ubuntu1 product
  • puma< 3.12.4-1ubuntu2+esm1 | < 5.5.2-2ubuntu2+esm1 | < 5.6.5-4ubuntu2

6 vendors · 11 products

References

17 links
Show all 17 references