net: wwan: iosm: bound device offsets in the MUX downlink decoder

Description

In the Linux kernel, the following vulnerability has been resolved: net: wwan: iosm: bound device offsets in the MUX downlink decoder mux_dl_adb_decode() walks a chain of aggregated datagram tables using offsets and lengths taken from the modem. first_table_index, next_table_index, table_length, datagram_index and datagram_length are all device supplied le values. Only first_table_index was checked, and only for being non zero. The decoder then formed adth = block + adth_index and read the table header and the datagram entries with no bound against the received skb. A modem that reports an index or a length past the downlink buffer makes the decoder read out of bounds. The buffer is IPC_MEM_MAX_DL_MUX_LITE_BUF_SIZE and skb->len is at most that, so skb->len is the real limit, but none of these in band offsets were checked against it. The table chain is also followed with no forward progress check. The loop takes the next table from adth->next_table_index and stops only when that reaches zero. A modem can stage two tables that point at each other, so the loop never ends. It runs in softirq and clones the skb on every pass. Validate every device offset and length against skb->len before use. The block header must fit. Each table header, on entry and after every next_table_index, must lie inside the skb. The datagram table must fit. Each datagram index and length must stay inside the skb. The header padding must not exceed the datagram length so the receive length does not wrap. Require each next_table_index to move forward so the chain cannot cycle. This was reproduced under KASAN as a slab out of bounds read on a normal downlink receive once the iosm net device is up.

Timeline

Scores

EPSS (exploitation in 30 days)

0.40% · top 65% of all CVEs (11 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: total

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.8.

Affected products

• Linux · Linux

  • affected 1f52d7b622854b8bd7a1be3de095ca2e1f77098e – < 155851e501d6c649cbcfcca6472dc26269b04b6b
  • affected 1f52d7b622854b8bd7a1be3de095ca2e1f77098e – < 2b822df8e498aa6ca828e16afd8ffec27f7e4c88
  • affected 1f52d7b622854b8bd7a1be3de095ca2e1f77098e – < 55cfea8e8d9117ad086d1e1a0ff87f306f8e3ad0
  • affected 1f52d7b622854b8bd7a1be3de095ca2e1f77098e – < 07f5eb6d268a37bd9e131079489655cd599182e0
  • affected 1f52d7b622854b8bd7a1be3de095ca2e1f77098e – < 77f0023f22f6a2616ae128e9c93961b24ae52611
  • affected 1f52d7b622854b8bd7a1be3de095ca2e1f77098e – < 526b8ef54668780c8f69e0211c342763d5dcbad1

• Linux · Linux

  • affected 5.18
  • unaffected < 5.18
  • unaffected 6.1.178 – ≤ 6.1.*
  • unaffected 6.6.145 – ≤ 6.6.*
  • unaffected 6.12.97 – ≤ 6.12.*
  • unaffected 6.18.40 – ≤ 6.18.*
  • unaffected 7.1.5 – ≤ 7.1.*
  • unaffected 7.2 – ≤ *

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• EUVD EUVD-2026-58987 (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisories (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-72029](https://cveledger.app/badge/CVE-2026-72029.svg)](https://cveledger.app/cve/CVE-2026-72029)

Record last updated 19 Oct 2026, 21:19 UTC.