CVE-2026-121727

Kore before 4.3.0 Integer Underflow Memory Exhaustion via http_header_recv()

CVSS score

8.7

EPSS probability

—

Risk score

0.9

Published

3 h ago

Overview Public Exploits (0)Newsroom Vulnerability Timeline

Official patch verified

Etkilenen ürün ve sürüm için yayımlanan güvenlik güncellemesini uygulayın.

Impact on My Inventory

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Vulnerability description

DayBreach AI Explanation

Verified against sources

Kore Integer Underflow Memory Exhaustion Vulnerability Prior to Version 4.3.0

Sources read

Source agreement

0/2

Evidence confidence

%44

Short explanation

Kore prior to version 4.3.0 contains an integer underflow vulnerability in HTTP request body handling. Unauthenticated attackers can bypass http_body_max limits by sending more body bytes than declared.

Why does it matter?

This security flaw allows attackers to exhaust worker memory and cause denial of service conditions. CVSS scoring differs between sources, with CVELIST reporting 8.7 and NVD reporting 7.5.

What should be done?

Update Kore software to version 4.3.0 or later
Apply the patch commit from official sources
Follow vendor advisories

Note on uncertainty

2 alanda kaynak uyuşmazlığı var. DayBreach bu değerleri saklamadı; kaynak karşılaştırması aşağıda gösteriliyor.

Chain of evidence and sources2 verified claims

Kore 4.3.0 öncesi sürümler, http_header_recv() içinde tamsayı alt akması zafiyeti barındırmaktadır.

S0 · daybreach-canonical S1 · cvelist S2 · nvd

Saldırganlar, bildirilen bayttan daha fazla gövde verisi göndererek http_body_max sınırını atlayabilir.

S0 · daybreach-canonical S1 · cvelist S2 · nvd

Show the technical text from the sources

Kore before 4.3.0 contains an integer underflow vulnerability in HTTP request body handling that allows unauthenticated attackers to bypass http_body_max by sending more body bytes than declared. Attackers can send oversized first segments over many concurrent POST, PUT or DELETE connections, wrapping content_length to grow buffers unbounded and exhaust worker memory.

CVSS vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

CWE: CWE-191

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-121727 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

ID	VENDOR	PRODUCT	ACTION
1	jorisvink	kore	View

Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCORE	VERSION	SEVERITY	VECTOR	SOURCE
8.7	CVSS V4_0	HIGH	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N	CVE CNA
8.7	CVSS V40	HIGH	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X	NVD
7.5	CVSS V3_1	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	CVE CNA
7.5	CVSS V31	HIGH	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	NVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch verified

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

cvelist

Patch Commit

Open source

reference

Patch Commit

Open source

Confirm the affected product and version against the source evidence above.

Restrict access to internet-facing services and apply network segmentation.

Apply the official update named in the evidence only to the matching product and version.

Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-121727 is associated with the following CWEs:

CWE-191: Common Weakness Enumeration Entry CWE-191

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-121727 weaknesses.

CAPEC-66: SQL Injection CAPEC-126: Path Traversal CAPEC-28: OS Command Injection

Attack Vector and Accessibility

ExposureAğ üzerinden

PermissionsGerekmiyor

UserGerekmiyor

Official Sources and Advisories

Patch Commitpatch https://github.com/jorisvink/korevendor-advisory Kore 4.3.0 Release Notesvendor-advisory https://github.com/jorisvink/kore/blob/4.3.0-rc5/src/http.c#L934vendor-advisory VulnCheck Advisory: Kore before 4.3.0 Integer Underflow Memory Exhaustion via http_header_recv()vendor-advisory

CVSS Vector Radar Chart

8.7 / 10

Vulnerability Scoring Details

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

Attack VectorNetwork

Attack ComplexityLow

Privileges RequiredNone required

User InteractionNone required

Confidentiality (Gizlilik)Low

Integrity (Bütünlük)None

Availability (Erişilebilirlik)High

Yama doğrulandı

2 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.

Follow the vendor

jorisvink

Weakness Type (CWE & CAPEC)

CWE-191

Get this vulnerability through the API

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