CVE-2026-42055
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NGINX ngx_http_proxy_v2_module and ngx_http_grpc_module vulnerability
rank 46 = 16 + 20 + 0 + 10 + 0
rank@v1 · this cycle
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.06537 · without this subject the record ranks 30
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 8.1, from the CNA · without this subject the record ranks 26
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 46
How much of the world it touches
NVD CPE configurations
20 products in the CPE ranges · without this subject the record ranks 36
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 46
$326,000 = $4.99M incident cost x 1 exposure x 0.06537 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
This record is one instance of CWE-122, heap-based buffer overflow. The index holds 3216 prior instances of this class, 20 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1
Running F5 NGINX Open Source? Check your version
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Harm, if it fires from the vector and the weakness
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CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Proof-of-concept published · 1 public repository, 2026-06-19.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published · 1 public repository2026-06-19receipt
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
Affected & Fixed Versions as published
Show all 20 published ranges
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
Attack path
What it is stated by the CNA
NGINX Plus and NGINX Open Source have a vulnerability in the ngx_http_proxy_v2_module and ngx_http_grpc_module modules. This vulnerability exists when the proxy_http_version to 2 or grpc_pass directives are used to proxy HTTP/2 traffic, the ignore_invalid_headers directive is set to off, and the large_client_header_buffers directive size is larger than 2 megabytes. A remote, unauthenticated attacker, along with conditions beyond their control, could send large headers while creating an upstream request. This may cause a heap-based buffer overflow in the NGINX worker process leading to a restart. receipt
Read the rest of the CNA's description
Additionally, attackers can execute code on systems with Address Space Layout Randomization (ASLR) disabled or when the attacker can bypass ASLR. Note: Software versions which have reached End of Technical Support (EoTS) are not evaluated.
NVD's analysis a second authority
- weakness
- CWE-122; CWE-787; CWE-131
- affected versions
- f5 nginx gateway fabric >= 1.3.0 <= 1.6.2; f5 nginx gateway fabric >= 2.0.0 <= 2.6.3; f5 nginx ingress controller >= 3.5.0 <= 3.7.2; and 17 more, listed in full below
- also scored by
- [email protected] 9.2 CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/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 · [email protected] 8.1…
Movement the material steps
Show all 11 observations
11 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The pattern, elsewhere
This record is one instance of CWE-122, heap-based buffer overflow. The index holds 3216 prior instances of this class, 20 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]
"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1
3216 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.
No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.
Siblings and hubs
Records related to this one
No record cites this identifier and it carries no alias. Its defect family is below.
Its defect family
f5 nginx open source
Of the 2 records in this family, this is the only one with public proof-of-concept code, and it holds 1 references to it.
Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.
Family membership: held values
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Browse the index from here
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What usually comes next
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