CVE-2026-109399

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Source
https://cve.org/CVERecord?id=CVE-2026-109399
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-109399.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-109399
Downstream
Published
2026-10-12T15:16:44Z
Modified
2026-10-14T07:02:31Z
Severity
  • 9.2 (Critical) CVSS_V4 - CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N CVSS Calculator
Summary
SWUpdate through 2026.05.1 CMS Signature Verification Bypass via Embedded Intermediates
Details

SWUpdate through 2026.05.1 contains an improper certificate validation vulnerability in crypto/swupdate_cms_verify_openssl.c that trusts untrusted X.509 certificates embedded in CMS SignedData for chain building. Attackers holding a signing key from a sibling intermediate under the same root can embed that intermediate in the signature to install malicious updates.

Database specific 
{
    "cna_assigner":  "VulnCheck",
    "cwe_ids":  [
        "CWE-295"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/109xxx/CVE-2026-109399.json"
}
References

Affected packages

Git / github.com/sbabic/swupdate

Affected ranges

Type
GIT
Repo
https://github.com/sbabic/swupdate
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
9000ecb52677da7d9676a61b729bab57dba99674
Fixed
e66c5640664a31668926a24c0c84b6b6570dc0d9
Database specific
Show details 
{
    "extracted_events":  [
        {
            "introduced":  "0"
        },
        {
            "fixed":  "2026.05.1"
        }
    ],
    "source":  [
        "DESCRIPTION",
        "REFERENCES"
    ]
}

Affected versions

2014.*
2014.07
2015.*
2015.07
2016.*
2016.04
2016.04-rc1
2016.07
2016.07-rc3
2016.10
2016.10-rc1
2017.*
2017.01
2017.01-rc1
2017.04
2017.04-rc1
2017.04-rc2
2017.07
2017.07-rc1
2017.11
2018.*
2018.03
2018.03-rc1
2018.11
2018.11-rc1
2019.*
2019.04
2019.04-rc1
2019.11
2019.11-rc1
2020.*
2020.04
2020.04-rc1
2020.04-rc2
2020.11
2021.*
2021.04
2021.11
2022.*
2022.05
2022.12
2023.*
2023.05
2023.12
2023.12.1
2024.*
2024.05
2024.05.2
2024.12
2025.*
2025.05
2025.12

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-109399.json"
vanir_signatures 
[
    {
        "deprecated":  false,
        "digest":  {
            "function_hash":  "99802814471114232091222288260174595927",
            "length":  1277
        },
        "id":  "CVE-2026-109399-3b9b7c88",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9",
        "target":  {
            "file":  "crypto/swupdate_cms_verify_openssl.c",
            "function":  "openssl_cms_verify_file"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
            "line_hashes":  [
                "253780004218998244180158764599123050743",
                "27909323336340585738616014031753920314",
                "255378846703955429197468271652729732151",
                "42411326248752732421032269485355189895",
                "245447065769167807011382437253220602104",
                "168154079082747109629301331100819004246",
                "442667799276524998080685203436406168",
                "16917437262173101105043893965429904919",
                "230519702706190606253488329177100382243",
                "108632204891208769763572761506482123465",
                "301281058260735907764271911668191948826",
                "255773589635677704853282807563083471078",
                "327274814017889380868282711972541787621",
                "60255760831286091237432165077716760481",
                "2790998237843039285543382244667475025",
                "34317222076138748161288059568737208746",
                "141086084863644303516205450463305866678",
                "262035361174700138356776415833556076629",
                "293905963165034859210746627150685161954",
                "334804067047338813805460294892750920165",
                "131653357935290966417162442837065526914",
                "24003336437452824156627227696921015766",
                "160535121033635519949813213374719949190",
                "147890596171450385942101356687946124386",
                "109012457875104728754490173831755169912",
                "65161608457873215749978378256574563425",
                "232140101387067267402458500131180634478",
                "99317853221238149562955401054326121116",
                "17949501504553802794078845524977926098",
                "197825630108359250941406903674727297974",
                "16722988320200991550939940869485549310",
                "178960911026378277316657285905131822295",
                "69156507821638884673433156632481209829",
                "53110275712911930935436224299190281692",
                "157445240408735625024229478306513259359"
            ],
            "threshold":  0.9
        },
        "id":  "CVE-2026-109399-42874ba7",
        "signature_type":  "Line",
        "signature_version":  "v1",
        "source":  "https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9",
        "target":  {
            "file":  "crypto/swupdate_cms_verify_openssl.c"
        }
    },
    {
        "deprecated":  false,
        "digest":  {
            "function_hash":  "9658556935862751931226300329695162123",
            "length":  993
        },
        "id":  "CVE-2026-109399-96fb27e4",
        "signature_type":  "Function",
        "signature_version":  "v1",
        "source":  "https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9",
        "target":  {
            "file":  "crypto/swupdate_cms_verify_openssl.c",
            "function":  "check_verified_signer"
        }
    }
]
vanir_signatures_modified 
"2026-10-14T07:02:31Z"