Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests.
This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.
“▲” beside the score: it is higher than the CVSS score beside it.
Score elevated to 7.6 because EPSS predicted 33% probability of exploitation within the next 30 days (98th percentile of EPSS-scored CVEs) when EchelonGraph scored this CVE. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 7.5 retained for reference (NVD's own analysis pending). Confidence: see factors.
Also known asEUVD-2026-35105 (ENISA EUVD) · GHSA-262v-g5h9-6mc6 (GitHub Security Advisories)Source: ENISA EUVD
A fix is available — apply it.
Memory Allocation with Excessive Size Value vulnerability in Apache HTTP Server's mod_http leads to denial of service via malicious HTTP requests.
This issue affects Apache HTTP Server: from 2.4.17 through 2.4.67.
EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
The EG score (7.6): severity, escalated by confirmed exploitation. This CVE's 7.6 is EPSS's lift toward 9.0 from its impact severity (EG Severity, CVSS 7.5 HIGH): a likelihood of exploitation, not impact.
SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it
June 8, 2026
August 19, 2026
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Red Hat Security Advisory: mod_http2 security update
Red Hat Security Advisory: mod_http2 security update
Red Hat Security Advisory: mod_http2 security update
Red Hat Security Advisory: mod_http2 security update
Red Hat Security Advisory: httpd:2.4 security update
Red Hat Security Advisory: httpd:2.4 security update
Red Hat Security Advisory: httpd:2.4 security update
Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.62 SP4 security update
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| apache2 | — |
| — |
| nginx | — |
| — |
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| apache2 | — |
| — |
| nginx | — |
| — |
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| apache2 | — |
| — |
| nginx | — |
| — |
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| apache2 | — |
| — |
| nginx | — |
| — |
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| apache2 | 2.4.48-3.1 ... 2.4.67-1~deb11u1 (83 versions) |
| — |
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| apache2 | 2.4.57-2 ... 2.4.67-1~deb12u2 (47 versions) |
| — |
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| apache2 | 2.4.65-2 ... 2.4.67-1~deb13u2 (23 versions) |
| — |
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| apache2 | 2.4.65-2 ... 2.4.67-1~deb13u3 (25 versions) |
| — |
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.
Showing the most recent 100 of 409 refreshes on record for this CVE.
A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 309 oldest rows on record are not shown and were not checked, so the counts can still include repeats.
Public exploit code is referenced for this CVE (9 GitHub PoCs), as is 1 GitHub checker repository. A GitHub repository named or described as a checker or scanner checks whether a system is affected; it is not necessarily exploit code. Defenders should treat patch urgency accordingly.
Security research PoC for CVE-2026-49975: HTTP/2 HPACK compression bomb + flow-control hold DoS in Apache mod_http2
Open source ↗HTTP/2 Bomb (CVE-2026-49975) non-destructive vulnerability detector for Nginx / Apache httpd. Zero-dependency Python.
Open source ↗HTTP2-Bomb
Open source ↗CVE-2026-49975
Open source ↗CVE-2026-49975漏洞复现
Open source ↗Disclosed on June 3, 2026, the "HTTP/2 Bomb" is an unauthenticated remote DoS that combines an HPACK compression bomb with a Slowloris-style hold to exhaust server memory. It affects default HTTP/2 configurations of **nginx, Apache httpd, Microsoft IIS, Envoy, and Cloudflare Pingora**.
Open source ↗CVE-2026-49975 HTTP/2 Stream Amplification — Docker PoC with Web Console
Open source ↗HTTP/2 Bomb PoC — CVE-2026-49975 (HPACK indexed reference bomb + flow-control stall)
Open source ↗Este repositorio contiene un Proof of Concept (POC) para CVE-2026-49975, también conocida como HTTP/2 Bomb, una vulnerabilidad de denegación de servicio (DoS) remoto que afecta a la mayoría de los servidores web principales en su configuración HTTP/2 predeterminada, incluyendo:
Open source ↗Alpine:v3.21:apache2
redhat:RHSA-2026:27200 · redhat:RHSA-2026:25042
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-49975
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