CURL-CVE-2026-86409

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Source
https://curl.se/docs/CVE-2026-86409.html
Import Source
https://curl.se/docs/CURL-CVE-2026-86409.json
JSON Data
https://api.osv.dev/v1/vulns/CURL-CVE-2026-86409
Aliases
  • CVE-2026-86409
Published
2026-10-14T08:00:00Z
Modified
2026-10-14T07:04:25Z
Summary
stale SigV4 headers sent unintended
Details

Setting CURLOPT_AWS_SIGV4 to NULL but does not disable SigV4 authentication, contrary to expectations and documentation. A subsequent transfer on the same handle still sends an Authorization: AWS4-HMAC-SHA256 header to whatever URL is set next, leaking state information.

Database specific 
{
    "CWE":  {
        "desc":  "Information Exposure Through Sent Data",
        "id":  "CWE-201"
    },
    "URL":  "https://curl.se/docs/CVE-2026-86409.json",
    "affects":  "lib",
    "issue":  "https://hackerone.com/reports/3973135",
    "last_affected":  "8.21.0",
    "package":  "curl",
    "severity":  "Low",
    "www":  "https://curl.se/docs/CVE-2026-86409.html"
}
Credits
    • Stanislav Fort (Aisle Research) - FINDER
    • Viktor Szakats - REMEDIATION_DEVELOPER

Affected packages

Git / github.com/curl/curl.git

Affected ranges

Type
SEMVER
Events
Introduced
7.75.0
Fixed
8.22.0
Type
GIT
Repo
https://github.com/curl/curl.git
Events
Introduced
08e8455dddc5e48e58a12ade3815c01ae3da3b64
Fixed
c3c70440e8d9938c0bb732595751e8aebc614f24

Affected versions

7.*
7.75.0
7.76.0
7.76.1
7.77.0
7.78.0
7.79.0
7.79.1
7.80.0
7.81.0
7.82.0
7.83.0
7.83.1
7.84.0
7.85.0
7.86.0
7.87.0
7.88.0
7.88.1
8.*
8.0.0
8.0.1
8.1.0
8.1.1
8.1.2
8.10.0
8.10.1
8.11.0
8.11.1
8.12.0
8.12.1
8.13.0
8.14.0
8.14.1
8.15.0
8.16.0
8.17.0
8.18.0
8.19.0
8.2.0
8.2.1
8.20.0
8.21.0
8.3.0
8.4.0
8.5.0
8.6.0
8.7.0
8.7.1
8.8.0
8.9.0
8.9.1
Other
curl-7_75_0
curl-7_76_0
curl-7_76_1
curl-7_77_0
curl-7_78_0
curl-7_79_0
curl-7_79_1
curl-7_80_0
curl-7_81_0
curl-7_82_0
curl-7_83_0
curl-7_83_1
curl-7_84_0
curl-7_85_0
curl-7_86_0
curl-7_87_0
curl-7_88_0
curl-7_88_1
curl-8_0_0
curl-8_0_1
curl-8_10_0
curl-8_10_1
curl-8_11_0
curl-8_11_1
curl-8_12_0
curl-8_12_1
curl-8_13_0
curl-8_14_0
curl-8_14_1
curl-8_15_0
curl-8_16_0
curl-8_17_0
curl-8_18_0
curl-8_19_0
curl-8_1_0
curl-8_1_1
curl-8_1_2
curl-8_20_0
curl-8_21_0
curl-8_2_0
curl-8_2_1
curl-8_3_0
curl-8_4_0
curl-8_5_0
curl-8_6_0
curl-8_7_0
curl-8_7_1
curl-8_8_0
curl-8_9_0
curl-8_9_1
rc-8_18_0-1
rc-8_18_0-2
rc-8_18_0-3
rc-8_19_0-1
rc-8_19_0-2
rc-8_19_0-3
rc-8_20_0-1
rc-8_20_0-2
rc-8_20_0-3
rc-8_21_0-1
rc-8_21_0-2
rc-8_21_0-3
rc-8_22_0-1
rc-8_22_0-2
rc-8_22_0-3
tiny-curl-8_4_0

Database specific

source 
"https://curl.se/docs/CURL-CVE-2026-86409.json"
vanir_signatures 
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        "id":  "CURL-CVE-2026-86409-62bc7d3a",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/curl/curl.git/commit/c3c70440e8d9938c0bb732595751e8aebc614f24",
        "target":  {
            "file":  "tests/libtest/lib1978.c",
            "function":  "test_lib1978"
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        }
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        "digest":  {
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            ],
            "threshold":  0.9
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        "id":  "CURL-CVE-2026-86409-aea9d465",
        "signature_type":  "Line",
        "signature_version":  "v1",
        "source":  "https://github.com/curl/curl.git/commit/c3c70440e8d9938c0bb732595751e8aebc614f24",
        "target":  {
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        "source":  "https://github.com/curl/curl.git/commit/c3c70440e8d9938c0bb732595751e8aebc614f24",
        "target":  {
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            "function":  "setopt_cptr_http_mqtt"
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]
vanir_signatures_modified 
"2026-10-14T07:04:25Z"