CVE-2026-1965

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Source
https://cve.org/CVERecord?id=CVE-2026-1965
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-1965.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-1965
Aliases
Downstream
Related
Published
2026-03-11T11:15:59.177Z
Modified
2026-03-14T15:05:40.618480Z
Severity
  • 6.5 (Medium) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N CVSS Calculator
Summary
[none]
Details

libcurl can in some circumstances reuse the wrong connection when asked to do an Negotiate-authenticated HTTP or HTTPS request.

libcurl features a pool of recent connections so that subsequent requests can reuse an existing connection to avoid overhead.

When reusing a connection a range of criterion must first be met. Due to a logical error in the code, a request that was issued by an application could wrongfully reuse an existing connection to the same server that was authenticated using different credentials. One underlying reason being that Negotiate sometimes authenticates connections and not requests, contrary to how HTTP is designed to work.

An application that allows Negotiate authentication to a server (that responds wanting Negotiate) with user1:password1 and then does another operation to the same server also using Negotiate but with user2:password2 (while the previous connection is still alive) - the second request wrongly reused the same connection and since it then sees that the Negotiate negotiation is already made, it just sends the request over that connection thinking it uses the user2 credentials when it is in fact still using the connection authenticated for user1...

The set of authentication methods to use is set with CURLOPT_HTTPAUTH.

Applications can disable libcurl's reuse of connections and thus mitigate this problem, by using one of the following libcurl options to alter how connections are or are not reused: CURLOPT_FRESH_CONNECT, CURLOPT_MAXCONNECTS and CURLMOPT_MAX_HOST_CONNECTIONS (if using the curl_multi API).

References

Affected packages

Git / github.com/curl/curl

Affected ranges

Type
GIT
Repo
https://github.com/curl/curl
Events
Introduced
bdb5e5a25037a585e0ec6b83d29b25961c6823f8
Fixed
8c908d2d0a6d32abdedda2c52e90bd56ec76c24d
Database specific 
{
    "versions": [
        {
            "introduced": "7.10.6"
        },
        {
            "fixed": "8.19.0"
        }
    ]
}

Affected versions

Other
before_ftp_statemachine
curl-7_10_6
curl-7_10_7
curl-7_10_8
curl-7_11_0
curl-7_11_1
curl-7_11_2
curl-7_12_0
curl-7_12_1
curl-7_12_2
curl-7_12_3
curl-7_13_0
curl-7_13_1
curl-7_13_2
curl-7_14_0
curl-7_14_1
curl-7_15_0
curl-7_15_1
curl-7_15_2
curl-7_15_3
curl-7_15_4
curl-7_15_5
curl-7_15_6-prepipeline
curl-7_16_0
curl-7_16_1
curl-7_16_2
curl-7_16_3
curl-7_16_4
curl-7_17_0
curl-7_17_0-preldapfix
curl-7_17_1
curl-7_18_0
curl-7_18_1
curl-7_18_2
curl-7_19_0
curl-7_19_1
curl-7_19_2
curl-7_19_3
curl-7_19_4
curl-7_19_5
curl-7_19_6
curl-7_19_7
curl-7_20_0
curl-7_20_1
curl-7_21_0
curl-7_21_1
curl-7_21_2
curl-7_21_3
curl-7_21_4
curl-7_21_5
curl-7_21_6
curl-7_21_7
curl-7_22_0
curl-7_23_0
curl-7_23_1
curl-7_24_0
curl-7_25_0
curl-7_26_0
curl-7_27_0
curl-7_28_0
curl-7_28_1
curl-7_29_0
curl-7_30_0
curl-7_31_0
curl-7_32_0
curl-7_33_0
curl-7_34_0
curl-7_35_0
curl-7_36_0
curl-7_37_0
curl-7_37_1
curl-7_38_0
curl-7_39_0
curl-7_40_0
curl-7_41_0
curl-7_42_0
curl-7_43_0
curl-7_44_0
curl-7_45_0
curl-7_46_0
curl-7_47_0
curl-7_47_1
curl-7_48_0
curl-7_49_0
curl-7_49_1
curl-7_50_0
curl-7_50_1
curl-7_50_2
curl-7_50_3
curl-7_51_0
curl-7_52_0
curl-7_52_1
curl-7_53_0
curl-7_53_1
curl-7_54_0
curl-7_54_1
curl-7_55_0
curl-7_55_1
curl-7_56_0
curl-7_56_1
curl-7_57_0
curl-7_58_0
curl-7_59_0
curl-7_60_0
curl-7_61_0
curl-7_61_1
curl-7_62_0
curl-7_63_0
curl-7_64_0
curl-7_64_1
curl-7_65_0
curl-7_65_1
curl-7_65_2
curl-7_65_3
curl-7_66_0
curl-7_67_0
curl-7_68_0
curl-7_69_0
curl-7_69_1
curl-7_70_0
curl-7_71_0
curl-7_71_1
curl-7_72_0
curl-7_73_0
curl-7_74_0
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_1_0
curl-8_1_1
curl-8_1_2
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

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-1965.json"