CVE-2026-5440 | Memory Exhaustion via Unbounded Content-Length

A memory exhaustion vulnerability exists in the HTTP server due to unbounded use of the `Content-Length` header. The server allocates memory directly based on the attacker supplied header value without enforcing an upper limit. A crafted HTTP request containing an extremely large `Content-Length` value can trigger excessive memory allocation and server termination, even without sending a request body.

Published: 2026-04-09 Last update: 2026-04-14 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-5440 is rated Moderate Risk (59.4/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.89%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-5440

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-11 1.64% 1.89% +0.25%
2 2026-04-15 0.02% 1.64% +1.61%
3 2026-04-10 — 0.02% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-5440

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-5440

OS Trackers for CVE-2026-5440

vendor priority summary link
debian not yet assigned CVE-2026-5440 not yet assigned priority: Debian including 1 source packages (orthanc), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 3, resolved 2. https://security-tracker.debian.org/tracker/CVE-2026-5440
ubuntu medium CVE-2026-5440 medium priority: Ubuntu including 1 source packages (orthanc), 8 status rows across 8 suites (bionic, focal, jammy, noble, questing, resolute, upstream, xenial): needs-triage 8. https://ubuntu.com/security/CVE-2026-5440

Affected software / configurations for CVE-2026-5440

Vendor Product Version Raw CPE
orthanc-server orthanc < 1.12.11 cpe:2.3:a:orthanc-server:orthanc:*:*:*:*:*:*:*:*

References for CVE-2026-5440

URL Tags
https://kb.cert.org/vuls/id/536588 Third Party Advisory VDB Entry
https://www.machinespirits.de/ Not Applicable
https://www.orthanc-server.com/ Product
cvelogic Threat Intelligence