Answer in brief
CVE-2021-47132 records a High severity (CVSS 7.5) vulnerability in mptcp: fix sk_forward_memory corruption on retransmission. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. 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). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25 <b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3 || >=64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25 <b5941f066b4ca331db225a976dae1d6ca8cf0ae3 || 96db8ffef07516a6d7414b6988f2a4298a839977 || >=5.11.4 <5.12 | b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3, b5941f066b4ca331db225a976dae1d6ca8cf0ae3, 5.12 |
| Linux/Linuxgeneric | 5.12 | Not reported |
Published upstream
Mar 15, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 4, 2026
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix sk_forward_memory corruption on retransmission MPTCP sk_forward_memory handling is a bit special, as such field is protected by the msk socket spin_lock, instead of the plain socket lock. Currently we have a code path updating such field without handling the relevant lock: __mptcp_retrans() -> __mptcp_clean_una_wakeup() Several helpers in __mptcp_clean_una_wakeup() will update sk_forward_alloc, possibly causing such field corruption, as reported by Matthieu. Address the issue providing and using a new variant of blamed function which explicitly acquires the msk spin lock.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2021-47132 records a High severity (CVSS 7.5) vulnerability in mptcp: fix sk_forward_memory corruption on retransmission. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. 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). Check affected ranges and fixed versions before updating.
| Product | Affected versions | Fixed versions |
|---|---|---|
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25 <b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3 || >=64b9cea7a0afe579dd2682f1f1c04f2e4e72fd25 <b5941f066b4ca331db225a976dae1d6ca8cf0ae3 || 96db8ffef07516a6d7414b6988f2a4298a839977 || >=5.11.4 <5.12 | b9c78b1a95966a7bd2ddae05b73eafc0cda4fba3, b5941f066b4ca331db225a976dae1d6ca8cf0ae3, 5.12 |
| Linux/Linuxgeneric | 5.12 | Not reported |
Published upstream
Mar 15, 2024
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Aug 4, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 4, 2026
In the Linux kernel, the following vulnerability has been resolved: mptcp: fix sk_forward_memory corruption on retransmission MPTCP sk_forward_memory handling is a bit special, as such field is protected by the msk socket spin_lock, instead of the plain socket lock. Currently we have a code path updating such field without handling the relevant lock: __mptcp_retrans() -> __mptcp_clean_una_wakeup() Several helpers in __mptcp_clean_una_wakeup() will update sk_forward_alloc, possibly causing such field corruption, as reported by Matthieu. Address the issue providing and using a new variant of blamed function which explicitly acquires the msk spin lock.
Quoted source text, attributed separately from HOL analysis.