CVE-2026-7790

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Source
https://cve.org/CVERecord?id=CVE-2026-7790
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-7790.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-7790
Aliases
Downstream
Published
2026-05-11T18:06:41.490Z
Modified
2026-07-08T08:12:41.202210593Z
Severity
  • 8.7 (High) CVSS_V4 - 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 CVSS Calculator
Summary
Unbounded chunk-size hex digits in cowlib cause quadratic CPU and memory DoS
Details

Uncontrolled Resource Consumption vulnerability in ninenines cowlib (cowhttpte module) allows Excessive Allocation.

The chunked transfer-encoding parser in cowhttpte accepts an unbounded number of hex digits in the chunk-size field. Each digit causes a bignum multiplication (Len * 16 + digit), so parsing N hex digits requires O(N²) CPU work and O(N) memory. Additionally, when input is drip-fed, the parser discards the accumulated length on each partial read and restarts from zero on resumption, raising the cost to O(N³). An unauthenticated remote attacker can exploit this by sending an HTTP/1.1 request with Transfer-Encoding: chunked and a very long chunk-size hex string to cause denial of service through CPU exhaustion and memory amplification.

This vulnerability is associated with program file src/cowhttpte.erl and program routines cowhttpte:streamchunked/2, cowhttpte:chunkedlen/4.

This issue affects cowlib: from 0.6.0 before 2.16.1.

Database specific 
{
    "unresolved_ranges": [
        {
            "source": "AFFECTED_FIELD",
            "extracted_events": [
                {
                    "introduced": "8c0e428b012c59f553a264f285ed89d36f791e3e"
                },
                {
                    "fixed": "a4b8039ce8c93ab00867ef6b7e888822c09f4369"
                }
            ]
        }
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/7xxx/CVE-2026-7790.json",
    "cna_assigner": "EEF",
    "cwe_ids": [
        "CWE-400"
    ]
}
References

Affected packages

Git / github.com/ninenines/cowlib

Affected ranges

Type
GIT
Repo
https://github.com/ninenines/cowlib
Events
Introduced
a6626f3b4539b07366034b4953ab2df29e3a9d58
Fixed
bae6b022af54566f3518a3aa59083b4591d552de
Fixed
a4b8039ce8c93ab00867ef6b7e888822c09f4369
Database specific 
{
    "source": [
        "CPE_RANGE",
        "REFERENCES"
    ],
    "cpe": "cpe:2.3:a:ninenines:cowlib:*:*:*:*:*:*:*:*",
    "extracted_events": [
        {
            "introduced": "0.6.0"
        },
        {
            "fixed": "2.16.1"
        }
    ]
}

Affected versions

0.*
0.6.0
0.6.1
0.6.2
1.*
1.0.0
1.0.1
1.1.0
1.2.0
1.3.0
2.*
2.0.0
2.0.0-pre.1
2.0.0-rc.1
2.0.1
2.1.0
2.10.0
2.10.1
2.11.0
2.12.0
2.12.1
2.13.0
2.14.0
2.15.0
2.16.0
2.2.0
2.2.1
2.3.0
2.4.0
2.5.0
2.5.1
2.6.0
2.7.0
2.7.1
2.7.2
2.7.3
2.8.0
2.9.0
2.9.1

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-7790.json"