Answer in brief
CVE-2024-26851 records a Unknown severity vulnerability in netfilter: nf_conntrack_h323: Add protection for bmp length out of range. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
Answer in brief
CVE-2024-26851 records a Unknown severity vulnerability in netfilter: nf_conntrack_h323: Add protection for bmp length out of range. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=5e35941d990123f155b02d5663e51a24f816b6f3 <98db42191329c679f4ca52bec0b319689e1ad8cb || >=5e35941d990123f155b02d5663e51a24f816b6f3 <4bafcc43baf7bcf93566394dbd15726b5b456b7a || >=5e35941d990123f155b02d5663e51a24f816b6f3 <ccd1108b16ab572d9bf635586b0925635dbd6bbc || >=5e35941d990123f155b02d5663e51a24f816b6f3 <b3c0f553820516ad4b62a9390ecd28d6f73a7b13 || >=5e35941d990123f155b02d5663e51a24f816b6f3 <39001e3c42000e7c2038717af0d33c32319ad591 || >=5e35941d990123f155b02d5663e51a24f816b6f3 <014a807f1cc9c9d5173c1cd935835553b00d211c || >=5e35941d990123f155b02d5663e51a24f816b6f3 <80ee5054435a11c87c9a4f30f1ff750080c96416 || >=5e35941d990123f155b02d5663e51a24f816b6f3 <767146637efc528b5e3d31297df115e85a2fd362 | 98db42191329c679f4ca52bec0b319689e1ad8cb, 4bafcc43baf7bcf93566394dbd15726b5b456b7a, ccd1108b16ab572d9bf635586b0925635dbd6bbc, b3c0f553820516ad4b62a9390ecd28d6f73a7b13, 39001e3c42000e7c2038717af0d33c32319ad591, 014a807f1cc9c9d5173c1cd935835553b00d211c, 80ee5054435a11c87c9a4f30f1ff750080c96416, 767146637efc528b5e3d31297df115e85a2fd362 |
| Linux/Linuxgeneric | 2.6.17 | Not reported |
| Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric | >=0 <* | * |
Published upstream
Apr 17, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: Add protection for bmp length out of range UBSAN load reports an exception of BRK#5515 SHIFT_ISSUE:Bitwise shifts that are out of bounds for their data type. vmlinux get_bitmap(b=75) + 712 <net/netfilter/nf_conntrack_h323_asn1.c:0> vmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, level=134443100) + 1956 <net/netfilter/nf_conntrack_h323_asn1.c:592> vmlinux decode_choice(base=0xFFFFFFD0080370F0, level=23843636) + 1216 <net/netfilter/nf_conntrack_h323_asn1.c:814> vmlinux decode_seq(f=0xFFFFFFD0080371A8, level=134443500) + 812 <net/netfilter/nf_conntrack_h323_asn1.c:576> vmlinux decode_choice(base=0xFFFFFFD008037280, level=0) + 1216 <net/netfilter/nf_conntrack_h323_asn1.c:814> vmlinux DecodeRasMessage() + 304 <net/netfilter/nf_conntrack_h323_asn1.c:833> vmlinux ras_help() + 684 <net/netfilter/nf_conntrack_h323_main.c:1728> vmlinux nf_confirm() + 188 <net/netfilter/nf_conntrack_proto.c:137> Due to abnormal data in skb->data, the extension bitmap length exceeds 32 when decoding ras message then uses the length to make a shift operation. It will change into negative after several loop. UBSAN load could detect a negative shift as an undefined behaviour and reports exception. So we add the protection to avoid the length exceeding 32. Or else it will return out of range error and stop decoding.
Quoted source text, attributed separately from HOL analysis.
A CVSS score is not reported in the current record. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystem (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=5e35941d990123f155b02d5663e51a24f816b6f3 <98db42191329c679f4ca52bec0b319689e1ad8cb || >=5e35941d990123f155b02d5663e51a24f816b6f3 <4bafcc43baf7bcf93566394dbd15726b5b456b7a || >=5e35941d990123f155b02d5663e51a24f816b6f3 <ccd1108b16ab572d9bf635586b0925635dbd6bbc || >=5e35941d990123f155b02d5663e51a24f816b6f3 <b3c0f553820516ad4b62a9390ecd28d6f73a7b13 || >=5e35941d990123f155b02d5663e51a24f816b6f3 <39001e3c42000e7c2038717af0d33c32319ad591 || >=5e35941d990123f155b02d5663e51a24f816b6f3 <014a807f1cc9c9d5173c1cd935835553b00d211c || >=5e35941d990123f155b02d5663e51a24f816b6f3 <80ee5054435a11c87c9a4f30f1ff750080c96416 || >=5e35941d990123f155b02d5663e51a24f816b6f3 <767146637efc528b5e3d31297df115e85a2fd362 | 98db42191329c679f4ca52bec0b319689e1ad8cb, 4bafcc43baf7bcf93566394dbd15726b5b456b7a, ccd1108b16ab572d9bf635586b0925635dbd6bbc, b3c0f553820516ad4b62a9390ecd28d6f73a7b13, 39001e3c42000e7c2038717af0d33c32319ad591, 014a807f1cc9c9d5173c1cd935835553b00d211c, 80ee5054435a11c87c9a4f30f1ff750080c96416, 767146637efc528b5e3d31297df115e85a2fd362 |
| Linux/Linuxgeneric | 2.6.17 | Not reported |
| Siemens/SIMATIC S7-1500 TM MFP - GNU/Linux subsystemgeneric | >=0 <* | * |
Published upstream
Apr 17, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 5, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 5, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: Add protection for bmp length out of range UBSAN load reports an exception of BRK#5515 SHIFT_ISSUE:Bitwise shifts that are out of bounds for their data type. vmlinux get_bitmap(b=75) + 712 <net/netfilter/nf_conntrack_h323_asn1.c:0> vmlinux decode_seq(bs=0xFFFFFFD008037000, f=0xFFFFFFD008037018, level=134443100) + 1956 <net/netfilter/nf_conntrack_h323_asn1.c:592> vmlinux decode_choice(base=0xFFFFFFD0080370F0, level=23843636) + 1216 <net/netfilter/nf_conntrack_h323_asn1.c:814> vmlinux decode_seq(f=0xFFFFFFD0080371A8, level=134443500) + 812 <net/netfilter/nf_conntrack_h323_asn1.c:576> vmlinux decode_choice(base=0xFFFFFFD008037280, level=0) + 1216 <net/netfilter/nf_conntrack_h323_asn1.c:814> vmlinux DecodeRasMessage() + 304 <net/netfilter/nf_conntrack_h323_asn1.c:833> vmlinux ras_help() + 684 <net/netfilter/nf_conntrack_h323_main.c:1728> vmlinux nf_confirm() + 188 <net/netfilter/nf_conntrack_proto.c:137> Due to abnormal data in skb->data, the extension bitmap length exceeds 32 when decoding ras message then uses the length to make a shift operation. It will change into negative after several loop. UBSAN load could detect a negative shift as an undefined behaviour and reports exception. So we add the protection to avoid the length exceeding 32. Or else it will return out of range error and stop decoding.
Quoted source text, attributed separately from HOL analysis.