Is CVE-2026-34826 in the CISA KEV catalog?

No. CVE-2026-34826 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-34826?

CVE-2026-34826 has a CVSS v3 base score of 5.3 (MEDIUM).

What is the EPSS score for CVE-2026-34826?

CVE-2026-34826 has an EPSS score of 0.38% (30th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2026-34826?

Upgrade ruby-rack on debian unstable to 3.2.6-2 or later. Fixes are available for 5 affected products.

CVE & CISA-KEV Catalog

CVE-2026-34826

MEDIUM

5.3

CVSS v3

NVD

Description

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Utils.get_byte_ranges parses the HTTP Range header without limiting the number of individual byte ranges. Although the existing fix for CVE-2024-26141 rejects ranges whose total byte coverage exceeds the file size, it does not restrict the count of ranges. An attacker can supply many small overlapping ranges such as 0-0,0-0,0-0,... to trigger disproportionate CPU, memory, I/O, and bandwidth consumption per request. This results in a denial of service condition in Rack file-serving paths that process multipart byte range responses. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

CWE-400Resource Exhaustion CWE-770Allocation of Resources Without Limits or Throttling

How to fix

Remediation Available

ruby-rackDebian

Fixed in:3.2.6-2CVE-2026-34826

librack-rubyUbuntu

Fixed in:1.5.2-3+deb8u3ubuntu1~esm11USN-8182-1

librack-ruby1.8Ubuntu

Fixed in:1.5.2-3+deb8u3ubuntu1~esm11USN-8182-1

librack-ruby1.9.1Ubuntu

Fixed in:1.5.2-3+deb8u3ubuntu1~esm11USN-8182-1

ruby-rackUbuntu

Fixed in:1.5.2-3+deb8u3ubuntu1~esm11USN-8182-1

Fixed in:1.6.4-3ubuntu0.2+esm10USN-8182-1

Fixed in:1.6.4-4ubuntu0.2+esm10USN-8182-1

Fixed in:2.0.7-2ubuntu0.1+esm10USN-8182-1

Fixed in:2.1.4-5ubuntu1.2+esm3USN-8182-1

Fixed in:2.2.7-1ubuntu0.7USN-8182-1

Fixed in:3.1.16-0.1ubuntu0.3USN-8182-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityLow

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Exploit Intelligence

0.38%probability of exploitation in 30 days

30thpercentile

Low risk: more likely to be exploited than 30% of all known CVEs.

References

Vendor Advisory1

github.com

Related Vulnerabilities

Other CWE-400 (Resource Exhaustion) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-44487	High	7.5	100%	KEV	Fix
CVE-2021-44228	Critical	10.0	100%	KEV + Ransom	Fix
CVE-2011-3192	High	7.8	99%	-	Fix
CVE-2019-11478	Medium	5.3	95%	-	Fix
CVE-2024-25617	Medium	5.3	89%	-	Fix
CVE-2018-1000115	High	7.5	89%	-	Fix

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-16.