Summary
It was discovered that the Linux kernel algif_aead module did not properly
handle in-place cryptographic operations. This flaw is known as Copy Fail.
A local attacker could use this to escalate privileges, or possibly escape
a container. (CVE-2026-31431)
Several security issues were discovered in the Linux kernel.
An attacker could possibly use these to compromise the system.
This update corrects flaws in the following subsystems:
- Cryptographic API;
- Packet sockets;
- TLS protocol;
(CVE-2026-31504, CVE-2026-31533, CVE-2026-43033, CVE-2026-43077,
CVE-2026-43078)
Fixed packages 3
| Release | Package | Fixed in |
|---|---|---|
| Ubuntu · Pro 18.04 LTS Pro:18.04:LTS | linux-azure-5.4 | 5.4.0-1163.169~18.04.1 |
| Ubuntu · Pro 20.04 LTS Pro:20.04:LTS | linux-azure | 5.4.0-1163.169 |
| Ubuntu · Pro FIPS-updates 20.04 LTS Pro:FIPS-updates:20.04:LTS | linux-azure-fips | 5.4.0-1163.169+fips1 |
Vulnerabilities 6
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High 7.8
crypto: algif_aead - Revert to operating out-of-place
In the Linux kernel, the following vulnerability has been resolved: crypto: algif_aead - Revert to operating out-of-place This mostly reverts commit 72548b093ee3 except for the copying of the associated data. There is no benefit in operating in-place in algif…
KEV May 1, 2026 -
Critical 9.8
net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption
In the Linux kernel, the following vulnerability has been resolved: net/tls: fix use-after-free in -EBUSY error path of tls_do_encryption The -EBUSY handling in tls_do_encryption(), introduced by commit 859054147318 ("net: tls: handle backlogging of crypto re…
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High 7.8
net: fix fanout UAF in packet_release() via NETDEV_UP race
In the Linux kernel, the following vulnerability has been resolved: net: fix fanout UAF in packet_release() via NETDEV_UP race `packet_release()` has a race window where `NETDEV_UP` can re-register a socket into a fanout group's `arr[]` array. The re-registra…
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High 7.8
crypto: authencesn - Do not place hiseq at end of dst for out-of-place decryption
In the Linux kernel, the following vulnerability has been resolved: crypto: authencesn - Do not place hiseq at end of dst for out-of-place decryption When decrypting data that is not in-place (src != dst), there is no need to save the high-order sequence bits…
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High 7.8
crypto: af_alg - Fix page reassignment overflow in af_alg_pull_tsgl
In the Linux kernel, the following vulnerability has been resolved: crypto: af_alg - Fix page reassignment overflow in af_alg_pull_tsgl When page reassignment was added to af_alg_pull_tsgl the original loop wasn't updated so it may try to reassign one more pa…
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Unscored —
crypto: algif_aead - Fix minimum RX size check for decryption
In the Linux kernel, the following vulnerability has been resolved: crypto: algif_aead - Fix minimum RX size check for decryption The check for the minimum receive buffer size did not take the tag size into account during decryption. Fix this by adding the re…