9.8 CRITICAL
- CVSS version (CVSS): 3.1
- Attack Vector (AV): Network (N)
- Attack Complexity (AC): Low (L)
- Privileges Required (PR): None (N)
- User Interaction (UI): None (N)
- Scope (S): Unchanged (U)
- Confidentiality (C): High (H)
- Integrity (I): High (H)
- Availability (A): High (H)
- Modified Attack Vector (MAV): Network (N)
- Modified Attack Complexity (MAC): Low (L)
- Modified Privileges Required (MPR): None (N)
- Modified User Interaction (MUI): None (N)
- Modified Confidentiality (MC): High (H)
- Modified Scope (MS): Unchanged (U)
- Modified Integrity (MI): High (H)
- Modified Availability (MA): High (H)
Activity log
- Created & dismissed (max. allowed matches exceeded) suggestion
ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress()
In the Linux kernel, the following vulnerability has been resolved: ipv6: rpl: fix hdrlen overflow in ipv6_rpl_srh_decompress() ipv6_rpl_srh_decompress() computes: outhdr->hdrlen = (((n + 1) * sizeof(struct in6_addr)) >> 3); hdrlen is __u8. For n >= 127 the result exceeds 255 and silently truncates. With n=127 (cmpri=15, cmpre=15, pad=0, hdrlen=16): (128 * 16) >> 3 = 256, truncated to 0 as __u8 The caller in ipv6_rpl_srh_rcv() then places the compressed header at buf + ((ohdr->hdrlen + 1) << 3). With hdrlen=0 this is buf + 8, but the decompressed region occupies buf[0..2055] (8-byte header plus 128 full addresses). The compressed header overlaps the decompressed data, and ipv6_rpl_srh_compress() writes into this overlap, corrupting the routing header of the forwarded packet. The existing guard at exthdrs.c:546 checks (n + 1) > 255, which prevents n+1 from overflowing unsigned char (the segments_left field), but does not prevent the computed hdrlen from overflowing __u8. n=127 passes because 128 <= 255, yet hdrlen=256 does not fit. Tighten the bound to (n + 1) > 127. This caps n at 126, giving hdrlen = (127 * 16) >> 3 = 254, which fits in __u8. The compressed header then lands at buf + ((254 + 1) << 3) = buf + 2040, exactly past the decompressed region (buf[0..2039]). No overlap. 127 segments is well beyond any realistic RPL deployment.
References
Affected products
- <97e06791368c01f0ad2a4b3269c2abe19485ca32
- <fd238c51b0fa5390cceca9f1ac5a9ffda8063eed
- <de02fc049352af5a9595f015511222d0a85c326b
- =<6.18.*
- =<7.0.*
- <c0487a9c1e116cf349e2d1f302d9019670460858
- <6fe1cb312038516cb4d9fa089d700af7059f1a64
- =<6.12.*
- =<5.15.*
- ==5.7
- =<6.1.*
- =<*
- <75b3680047bf09af8e7e471a7a6ddf2ce5847f56
- =<6.6.*
- <3618b34942b76471d044369bfd30d58c39068bf1
- <9d5e7a46a9f6d8f503b41bfefef70659845f1679
- =<5.10.*
- <5.7