Answer in brief
CVE-2026-63993 records a Unknown severity vulnerability in vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu(). 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.
Answer in brief
CVE-2026-63993 records a Unknown severity vulnerability in vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu(). 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.
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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <6b8bfce9d2f774d2c2243e0248e03efb99bba6c0 || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <9257f56ac47ef1976bcd056cf986a9988eeec67a || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <8d435d68d71fb875876b722f4136caf74f2f48bd || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <dc3bfa050f873371e745bdf478b1f5b738e5733d || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <609e63312c29aad18026a1d3222e123d4b6b0feb || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <5303925e360527243b46a440a04667826bbc72b7 || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <a493efd4336cf19122ae0e4cbb3d31b32d70deea || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <7d9ef0cb271555d8cf39fefe6c981e1493b25ecf | 6b8bfce9d2f774d2c2243e0248e03efb99bba6c0, 9257f56ac47ef1976bcd056cf986a9988eeec67a, 8d435d68d71fb875876b722f4136caf74f2f48bd, dc3bfa050f873371e745bdf478b1f5b738e5733d, 609e63312c29aad18026a1d3222e123d4b6b0feb, 5303925e360527243b46a440a04667826bbc72b7, a493efd4336cf19122ae0e4cbb3d31b32d70deea, 7d9ef0cb271555d8cf39fefe6c981e1493b25ecf |
| Linux/Linuxgeneric | 5.9 | Not reported |
Published upstream
Jul 19, 2026
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: vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() skb_tunnel_check_pmtu() can change skb->head. Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF. Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c. Found by Sashiko.
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). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <6b8bfce9d2f774d2c2243e0248e03efb99bba6c0 || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <9257f56ac47ef1976bcd056cf986a9988eeec67a || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <8d435d68d71fb875876b722f4136caf74f2f48bd || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <dc3bfa050f873371e745bdf478b1f5b738e5733d || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <609e63312c29aad18026a1d3222e123d4b6b0feb || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <5303925e360527243b46a440a04667826bbc72b7 || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <a493efd4336cf19122ae0e4cbb3d31b32d70deea || >=4cb47a8644cc9eb8ec81190a50e79e6530d0297f <7d9ef0cb271555d8cf39fefe6c981e1493b25ecf | 6b8bfce9d2f774d2c2243e0248e03efb99bba6c0, 9257f56ac47ef1976bcd056cf986a9988eeec67a, 8d435d68d71fb875876b722f4136caf74f2f48bd, dc3bfa050f873371e745bdf478b1f5b738e5733d, 609e63312c29aad18026a1d3222e123d4b6b0feb, 5303925e360527243b46a440a04667826bbc72b7, a493efd4336cf19122ae0e4cbb3d31b32d70deea, 7d9ef0cb271555d8cf39fefe6c981e1493b25ecf |
| Linux/Linuxgeneric | 5.9 | Not reported |
Published upstream
Jul 19, 2026
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: vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu() skb_tunnel_check_pmtu() can change skb->head. Reusing old_iph afer skb_tunnel_check_pmtu() can cause an UAF. Use instead ip_hdr(skb) as done in drivers/net/bareudp.c and drivers/net/geneve.c. Found by Sashiko.
Quoted source text, attributed separately from HOL analysis.