High
opendkim — security advisory
A weakness has been identified in Trusted Domain Project OpenDKIM up to 2.11.0. This affects the function dkim_canon_selecthdrs of the file libopendkim/dkim-canon.c of the component DKIM Signature Header Selection. Executing a manipulation of the argument h can lead to out-of-bounds write. The attack can be executed remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.
- Products
- opendkim
- Affected versions
- 2.10.3-3build1, 2.11.0~alpha-10, 2.11.0~alpha-11, 2.11.0~alpha-11build1, 2.11.0~alpha-12, 2.11.0~alpha-13, 2.11.0~alpha-14, 2.11.0~beta2-1, 2.11.0~beta2-4build1, 2.11.0~beta2-5, 2.11.0~beta2-6, 2.11.0~beta2-8, 2.11.0~beta2-9, 2.11.0~beta2-9.2, 2.11.0~beta2-9.2build1, 2.11.0~beta2-9.2build2, 2.11.0~beta2-9build3, 2.11.0~beta2-9build4
- Fixed versions
- Not specified
- CVEs
- CVE-2026-100888
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:53 UTC · Revision 1
Source evidence
A weakness has been identified in Trusted Domain Project OpenDKIM up to 2.11.0. This affects the function dkim_canon_selecthdrs of the file libopendkim/dkim-canon.c of the component DKIM Signature Header Selection. Executing a manipulation of the argument h can lead to out-of-bounds write. The attack can be executed remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.
osv:UBUNTU-CVE-2026-100888
opendkim
Fixed versions: Not specified
opendkim
Fixed versions: Not specified
opendkim
Fixed versions: Not specified
opendkim
Fixed versions: Not specified
opendkim
Fixed versions: Not specified
opendkim
Fixed versions: Not specified
opendkim
Fixed versions: Not specified
Complete source record
{
"id": "a18f6fab6ab1c1186ab1c4ab4c3a2b1bccd88bed44d8b8325460a42771602008",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-100888",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-100888",
"summary": "A weakness has been identified in Trusted Domain Project OpenDKIM up to 2.11.0. This affects the function dkim_canon_selecthdrs of the file libopendkim/dkim-canon.c of the component DKIM Signature Header Selection. Executing a manipulation of the argument h can lead to out-of-bounds write. The attack can be executed remotely. The exploit has been made available to the public and could be used for attacks. The vendor was contacted early about this disclosure but did not respond in any way.",
"evidence": "osv:UBUNTU-CVE-2026-100888",
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],
"severity": "high",
"structured": {
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"aliases": [
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"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L"
},
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P"
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{
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},
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{
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],
"modified": "2026-10-17T12:59:42.267140447Z",
"provider": "osv",
"upstream": [
"CVE-2026-100888"
],
"references": [
"https://ubuntu.com/security/CVE-2026-100888",
"https://www.cve.org/CVERecord?id=CVE-2026-100888",
"https://weitongli.com/share/opendkim-h-tag-oob-write.html",
"https://vuldb.com/cve/CVE-2026-100888",
"https://vuldb.com/submit/917015",
"https://vuldb.com/vuln/410837",
"https://vuldb.com/vuln/410837/cti"
]
},
"related_cves": [
{
"value": "CVE-2026-100888",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 359719,
"published_at": "2026-09-28T00:16:00+00:00"
}