cve-2026-8927
CRITICAL CVSS 9.1 nvd
Description
When reusing a libcurl handle for sequential transfers driven by environment-variable proxy configuration, libcurl fails to clear the proxy authentication state between requests. Specifically, if the initial transfer authenticates against `proxyA` using Digest auth, a subsequent transfer routed through `proxyB` erroneously leaks the `Proxy-Authorization:` header intended solely for `proxyA`.
Timeline
- Published
- 2026-07-03
- Last Modified
- 2026-09-15
CVSS Details
- Attack Vector
- NETWORK
- Attack Complexity
- LOW
- Privileges Required
- NONE
Affected Products
- haxx curl
Weaknesses (CWE)
CVSS metrics
| Version | Base | Severity | Vector | Exploitability | Impact | Source |
|---|---|---|---|---|---|---|
| 3.1 | 9.1 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N |
3.9 | 5.2 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
CPE configurations
OR
| CPE | Version range | Vulnerable |
|---|---|---|
cpe:2.3:a:haxx:curl:*:*:*:*:*:*:*:* |
>= 7.12.0, < 8.21.0 | yes |
NVD metadata
- NVD status
- Modified
- Source identifier
2499f714-1537-4658-8207-48ae4bb9eae9
References
- https://curl.se/docs/CVE-2026-8927.html Patch, Vendor Advisory
- https://curl.se/docs/CVE-2026-8927.json Vendor Advisory
- https://hackerone.com/reports/3744543 Exploit, Issue Tracking, Third Party Advisory
Linked Vulnerabilities
{
"cvss": 9.1,
"datePublished": "2026-07-03T07:16:25.123",
"dateUpdated": "2026-09-15T07:16:33.157",
"description": "When reusing a libcurl handle for sequential transfers driven by\nenvironment-variable proxy configuration, libcurl fails to clear the proxy\nauthentication state between requests. Specifically, if the initial transfer\nauthenticates against `proxyA` using Digest auth, a subsequent transfer routed\nthrough `proxyB` erroneously leaks the `Proxy-Authorization:` header intended\nsolely for `proxyA`.",
"id": "CVE-2026-8927",
"raw": {
"affected": [
{
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}
]
},
{
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{
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"source": "2499f714-1537-4658-8207-48ae4bb9eae9"
}
],
"configurations": [
{
"nodes": [
{
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{
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "When reusing a libcurl handle for sequential transfers driven by\nenvironment-variable proxy configuration, libcurl fails to clear the proxy\nauthentication state between requests. Specifically, if the initial transfer\nauthenticates against `proxyA` using Digest auth, a subsequent transfer routed\nthrough `proxyB` erroneously leaks the `Proxy-Authorization:` header intended\nsolely for `proxyA`."
}
],
"id": "CVE-2026-8927",
"lastModified": "2026-09-15T07:16:33.157",
"metrics": {
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{
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"attackVector": "NETWORK",
"availabilityImpact": "NONE",
"baseScore": 9.1,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N",
"version": "3.1"
},
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"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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{
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"role": "CISA Coordinator",
"timestamp": "2026-07-06T17:00:13.489405Z",
"version": "2.0.3"
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},
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],
"sourceIdentifier": "2499f714-1537-4658-8207-48ae4bb9eae9",
"vulnStatus": "Modified",
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{
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"value": "CWE-294"
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"source": "nvd@nist.gov",
"type": "Primary"
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]
},
"severity": "CRITICAL",
"source": "nvd",
"title": "When reusing a libcurl handle for sequential transfers driven by\nenvironment-variable proxy configuration, libcurl fa..."
}
Enrichment data
Aggregated bundle (all enrichments)