CVE-2021-44790
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Possible buffer overflow when parsing multipart content in mod_lua of Apache HTTP Server 2.4.51 and earlier
rank 66 = 30 + 25 + 1 + 10 + 0
rank@v1 · this cycle
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.96840 · without this subject the record ranks 36
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 9.8, from NVD · without this subject the record ranks 41
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
rose on 2025-11-18 · without this subject the record ranks 65
How much of the world it touches
NVD CPE configurations
20 products in the CPE ranges · without this subject the record ranks 56
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 66
$4.83M = $4.99M incident cost x 1 exposure x 0.9684 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-787, out-of-bounds write. The index holds 14893 prior instances of this class, 164 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1
Running Apache HTTP Server? 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 · 2 public repositories, 2023-12-05.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published · 2 public repositories2023-12-05receipt
- 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.
What it is stated by the CNA
A carefully crafted request body can cause a buffer overflow in the mod_lua multipart parser (r:parsebody() called from Lua scripts). The Apache httpd team is not aware of an exploit for the vulnerabilty though it might be possible to craft one. This issue affects Apache HTTP Server 2.4.51 and earlier. receipt
NVD's analysis a second authority
- severity
- 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- weakness
- CWE-787
- affected versions
- apache http server < 2.4.52; oracle http server 12.2.1.3.0; oracle http server 12.2.1.4.0; and 17 more, listed in full below
check it yourself httpd.apache.org openwall.com lists.fedoraproject.org debian.org oracle.com security.netapp.com +14 morereceipt
Dated events
Movement the material steps
This score more than doubled inside 72 hours. Both observations are in the full history below.
Show all 97 observations
97 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-787, out-of-bounds write. The index holds 14893 prior instances of this class, 164 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
14893 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
apache software foundation apache http server
Of the 5 records in this family, this is the only one with public proof-of-concept code, and it holds 2 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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