Answer in brief
CVE-2026-52999 records a Critical severity (CVSS 9.1) vulnerability in netfilter: nfnetlink_osf: fix out-of-bounds read on option matching. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. 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 9.1. 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 CPU 1518-4 PN/DP MFP (generic), Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (generic) and additional mapped packages. 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:5.0:-:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.0:rc5:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.0:rc6:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.0:rc7:*:*:*:*:*:* | Not reported | Not reported |
| cpe:2.3:o:linux:linux_kernel:5.0:rc8:*:*:*:*:*:* | Not reported | Not reported |
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=1a6a0951fc009f6d9fe8ebea2d2417d80d54097b <0145548346c4a30981a870a8ca00eac46ba27e85 || >=1a6a0951fc009f6d9fe8ebea2d2417d80d54097b <1c136f2c44a5913646bac85303612fd0825197a0 || >=1a6a0951fc009f6d9fe8ebea2d2417d80d54097b <1e19a07291bb8682c14c39a64725a3ae54ab8ccc || >=1a6a0951fc009f6d9fe8ebea2d2417d80d54097b <32e50f92c7cf3f4eba29622179a5fcdc2aebab41 || >=1a6a0951fc009f6d9fe8ebea2d2417d80d54097b <70a3f31d25cf2ec9d4ddfa408120171ead955623 || >=1a6a0951fc009f6d9fe8ebea2d2417d80d54097b <21883587593d7c8bb519a79460a0b5bc5ffbdabd || >=1a6a0951fc009f6d9fe8ebea2d2417d80d54097b <edb78a142d2e5948e63647c0646aa7e7886935f0 || >=1a6a0951fc009f6d9fe8ebea2d2417d80d54097b <f5ca450087c3baf3651055e7a6de92600f827af3 || 0c1054e0e5fdef2369fb089e94def978bd209e1f || 8316b60582facd4068fb0916c4db2418c21b7174 || >=4.19.26 <4.20 || >=4.20.13 <4.21 | 0145548346c4a30981a870a8ca00eac46ba27e85, 1c136f2c44a5913646bac85303612fd0825197a0, 1e19a07291bb8682c14c39a64725a3ae54ab8ccc, 32e50f92c7cf3f4eba29622179a5fcdc2aebab41, 70a3f31d25cf2ec9d4ddfa408120171ead955623, 21883587593d7c8bb519a79460a0b5bc5ffbdabd, edb78a142d2e5948e63647c0646aa7e7886935f0, f5ca450087c3baf3651055e7a6de92600f827af3, 4.20, 4.21 |
| Linux/Linuxgeneric | 5.0 | Not reported |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.7 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPgeneric | >=V3.1.7 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.6 <* | * |
| Siemens/SIPLUS S7-1500 CPU 1518-4 PN/DP MFPgeneric | >=V3.1.7 <* | * |
Published upstream
Jun 24, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 19, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 24, 2026
In the Linux kernel, the following vulnerability has been resolved: netfilter: nfnetlink_osf: fix out-of-bounds read on option matching In nf_osf_match(), the nf_osf_hdr_ctx structure is initialized once and passed by reference to nf_osf_match_one() for each fingerprint checked. During TCP option parsing, nf_osf_match_one() advances the shared ctx->optp pointer. If a fingerprint perfectly matches, the function returns early without restoring ctx->optp to its initial state. If the user has configured NF_OSF_LOGLEVEL_ALL, the loop continues to the next fingerprint. However, because ctx->optp was not restored, the next call to nf_osf_match_one() starts parsing from the end of the options buffer. This causes subsequent matches to read garbage data and fail immediately, making it impossible to log more than one match or logging incorrect matches. Instead of using a shared ctx->optp pointer, pass the context as a constant pointer and use a local pointer (optp) for TCP option traversal. This makes nf_osf_match_one() strictly stateless from the caller's perspective, ensuring every fingerprint check starts at the correct option offset.
Quoted source text, attributed separately from HOL analysis.