Medium
mruby — security advisory
A flaw has been found in mruby up to 3.4.0. This affects the function mrb_vm_exec of the file src/vm.c of the component JMPNOT-to-JMPIF Optimization. Executing a manipulation can lead to use after free. The attack needs to be launched locally. The exploit has been published and may be used. This patch is called e50f15c1c6e131fa7934355eb02b8173b13df415. It is advisable to implement a patch to correct this issue.
- Products
- mruby
- Affected versions
- 1.1.0+20150817+gita1731254-1, 1.1.0+20150906+git1cbbb7e1-1, 1.2.0+20160315+git4f20d58a-1, 1.3.0+20170925+git38185028-1, 1.3.0+20171029+git77edafb0-1, 1.3.0-1, 1.4.0-1, 2.0.0-1, 2.1.2-3, 3.0.0-1, 3.0.0-3, 3.2.0-1, 3.2.0-2, 3.3.0-1, 3.4.0-2, 3.4.0-3, 4.0.0-1
- Fixed versions
- Not specified
- CVEs
- CVE-2026-1979
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 31 Oct 2026, 02:41 UTC · Revision 1
Source evidence
A flaw has been found in mruby up to 3.4.0. This affects the function mrb_vm_exec of the file src/vm.c of the component JMPNOT-to-JMPIF Optimization. Executing a manipulation can lead to use after free. The attack needs to be launched locally. The exploit has been published and may be used. This patch is called e50f15c1c6e131fa7934355eb02b8173b13df415. It is advisable to implement a patch to correct this issue.
osv:UBUNTU-CVE-2026-1979
mruby
Fixed versions: Not specified
mruby
Fixed versions: Not specified
mruby
Fixed versions: Not specified
mruby
Fixed versions: Not specified
mruby
Fixed versions: Not specified
mruby
Fixed versions: Not specified
mruby
Fixed versions: Not specified
mruby
Fixed versions: Not specified
Complete source record
{
"id": "0dcfc26b95074f61c2c121227f9ec5d5276e00064e5fbb4a4acef176b0cd79dc",
"url": "https://osv.dev/vulnerability/UBUNTU-CVE-2026-1979",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "UBUNTU-CVE-2026-1979",
"summary": "A flaw has been found in mruby up to 3.4.0. This affects the function mrb_vm_exec of the file src/vm.c of the component JMPNOT-to-JMPIF Optimization. Executing a manipulation can lead to use after free. The attack needs to be launched locally. The exploit has been published and may be used. This patch is called e50f15c1c6e131fa7934355eb02b8173b13df415. It is advisable to implement a patch to correct this issue.",
"evidence": "osv:UBUNTU-CVE-2026-1979",
"products": [
{
"name": {
"value": "mruby",
"evidence": "/affected/0/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.1.0+20150817+gita1731254-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.1.0+20150906+git1cbbb7e1-1",
"evidence": "/affected/0/versions"
},
{
"value": "1.2.0+20160315+git4f20d58a-1",
"evidence": "/affected/0/versions"
}
]
},
{
"name": {
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"evidence": "/affected/1/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "1.3.0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.3.0+20170925+git38185028-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.3.0+20171029+git77edafb0-1",
"evidence": "/affected/1/versions"
},
{
"value": "1.4.0-1",
"evidence": "/affected/1/versions"
}
]
},
{
"name": {
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"evidence": "/affected/2/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "2.0.0-1",
"evidence": "/affected/2/versions"
}
]
},
{
"name": {
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"evidence": "/affected/3/package/name"
},
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"affected_versions": [
{
"value": "2.1.2-3",
"evidence": "/affected/3/versions"
},
{
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"evidence": "/affected/3/versions"
},
{
"value": "3.0.0-3",
"evidence": "/affected/3/versions"
}
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},
{
"name": {
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"evidence": "/affected/4/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.2.0-1",
"evidence": "/affected/4/versions"
},
{
"value": "3.2.0-2",
"evidence": "/affected/4/versions"
}
]
},
{
"name": {
"value": "mruby",
"evidence": "/affected/5/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.3.0-1",
"evidence": "/affected/5/versions"
}
]
},
{
"name": {
"value": "mruby",
"evidence": "/affected/6/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.4.0-2",
"evidence": "/affected/6/versions"
},
{
"value": "3.4.0-3",
"evidence": "/affected/6/versions"
},
{
"value": "4.0.0-1",
"evidence": "/affected/6/versions"
}
]
},
{
"name": {
"value": "mruby",
"evidence": "/affected/7/package/name"
},
"prerequisites": [],
"fixed_versions": [],
"affected_versions": [
{
"value": "3.3.0-1",
"evidence": "/affected/7/versions"
},
{
"value": "3.4.0-2",
"evidence": "/affected/7/versions"
}
]
}
],
"severity": "medium",
"structured": {
"id": "UBUNTU-CVE-2026-1979",
"aliases": [
"UBUNTU-CVE-2026-1979"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L"
},
{
"type": "CVSS_V3",
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
},
{
"type": "CVSS_V4",
"score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P"
},
{
"type": "Ubuntu",
"score": "medium"
}
],
"affected": [
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "mruby",
"purl": "pkg:deb/ubuntu/mruby?arch=source&distro=xenial",
"ecosystem": "Ubuntu:16.04:LTS"
},
"versions": [
"1.1.0+20150817+gita1731254-1",
"1.1.0+20150906+git1cbbb7e1-1",
"1.2.0+20160315+git4f20d58a-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-1979.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "mruby",
"binary_version": "1.2.0+20160315+git4f20d58a-1"
}
]
}
},
{
"ranges": [
{
"type": "ECOSYSTEM",
"events": [
{
"introduced": "0"
}
]
}
],
"package": {
"name": "mruby",
"purl": "pkg:deb/ubuntu/mruby?arch=source&distro=bionic",
"ecosystem": "Ubuntu:18.04:LTS"
},
"versions": [
"1.3.0-1",
"1.3.0+20170925+git38185028-1",
"1.3.0+20171029+git77edafb0-1",
"1.4.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-1979.json"
},
"ecosystem_specific": {
"binaries": [
{
"binary_name": "mruby",
"binary_version": "1.4.0-1"
}
]
}
},
{
"ranges": [
{
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],
"package": {
"name": "mruby",
"purl": "pkg:deb/ubuntu/mruby?arch=source&distro=focal",
"ecosystem": "Ubuntu:20.04:LTS"
},
"versions": [
"2.0.0-1"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-1979.json"
},
"ecosystem_specific": {
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{
"binary_name": "mruby",
"binary_version": "2.0.0-1"
}
]
}
},
{
"ranges": [
{
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"package": {
"name": "mruby",
"purl": "pkg:deb/ubuntu/mruby?arch=source&distro=jammy",
"ecosystem": "Ubuntu:22.04:LTS"
},
"versions": [
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"3.0.0-1",
"3.0.0-3"
],
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"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-1979.json"
},
"ecosystem_specific": {
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{
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"ecosystem": "Ubuntu:24.04:LTS"
},
"versions": [
"3.2.0-1",
"3.2.0-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-1979.json"
},
"ecosystem_specific": {
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},
{
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"package": {
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"ecosystem": "Ubuntu:25.10"
},
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"3.3.0-1"
],
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},
"ecosystem_specific": {
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"ecosystem": "Ubuntu:26.10"
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"versions": [
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"3.4.0-3",
"4.0.0-1"
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},
"ecosystem_specific": {
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},
{
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"ecosystem": "Ubuntu:26.04:LTS"
},
"versions": [
"3.3.0-1",
"3.4.0-2"
],
"database_specific": {
"source": "https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-1979.json"
},
"ecosystem_specific": {
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"binary_version": "3.4.0-2"
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}
],
"modified": "2026-10-17T12:58:46.404545361Z",
"provider": "osv",
"upstream": [
"CVE-2026-1979"
],
"references": [
"https://ubuntu.com/security/CVE-2026-1979",
"https://www.cve.org/CVERecord?id=CVE-2026-1979",
"https://github.com/mruby/mruby/issues/6701",
"https://github.com/sysfce2/mruby/commit/e50f15c1c6e131fa7934355eb02b8173b13df415",
"https://github.com/mruby/mruby/",
"https://github.com/mruby/mruby/issues/6701#issue-3802609843",
"https://vuldb.com/?ctiid.344501",
"https://vuldb.com/?id.344501",
"https://vuldb.com/?submit.743377"
]
},
"related_cves": [
{
"value": "CVE-2026-1979",
"evidence": "/upstream"
}
],
"security_relevant": true,
"severity_evidence": "/severity/1/score"
},
"source_id": "core-osv",
"document_id": 359034,
"published_at": "2026-02-06T05:16:00+00:00"
}