CVE-2026-46307

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

wifi: ath5k: do not access array OOB

Vincent reports:

The ath5k driver seems to do an array-index-out-of-bounds access as shown by the UBSAN kernel message: UBSAN: array-index-out-of-bounds in drivers/net/wireless/ath/ath5k/base.c:1741:20 index 4 is out of range for type ieee80211_tx_rate [4] … Call Trace: dump_stack_lvl+0x5d/0x80 ubsan_epilogue+0x5/0x2b __ubsan_handle_out_of_bounds.cold+0x46/0x4b ath5k_tasklet_tx+0x4e0/0x560 [ath5k] tasklet_action_common+0xb5/0x1c0

It is real. ts->ts_final_idx can be 3 on 5212, so: info->status.rates[ts->ts_final_idx + 1].idx = -1; with the array defined as: struct ieee80211_tx_rate rates[IEEE80211_TX_MAX_RATES]; while the size is: #define IEEE80211_TX_MAX_RATES 4 is indeed bogus.

Set this idx = -1 sentinel only if the array index is less than the array size. As mac80211 will not look at rates beyond the size (IEEE80211_TX_MAX_RATES).

Note: The effect of the OOB write is negligible. It just overwrites the next member of info->status, i.e. ack_signal.

Weakness

The product reads data past the end, or before the beginning, of the intended buffer.

Affected Software

Potential Mitigations

• Assume all input is malicious. Use an “accept known good” input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
• When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, “boat” may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as “red” or “blue.”
• Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code’s environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
• To reduce the likelihood of introducing an out-of-bounds read, ensure that you validate and ensure correct calculations for any length argument, buffer size calculation, or offset. Be especially careful of relying on a sentinel (i.e. special character such as NUL) in untrusted inputs.

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/540.html

References

• https://git.kernel.org/stable/c/568173ad9bd0b46cc6cd937dea8791e9b5eefa57
• https://git.kernel.org/stable/c/744c19e266b0d2628c5951439195dcef27eadacf
• https://git.kernel.org/stable/c/83226c71af53fb9b3cad40cb9a9a79f36d68c020
• https://git.kernel.org/stable/c/9dd6aae4bc7bfa11088d928670a3315eae542769
• https://git.kernel.org/stable/c/d6869537013b1f21b292342752d97868b79b5934
• https://git.kernel.org/stable/c/d748603f12baff112caa3ab7d39f50100f010dbd
• https://git.kernel.org/stable/c/e9f1081bc775146156def0dbc821b92f35d56afb
• https://git.kernel.org/stable/c/ecb1c163166759dec004c1fdb9709b8a5992fc8e