Summary
It was discovered that a logic flaw existed in the XFRM ESP-in-TCP
subsystem in the Linux kernel when handling socket buffer fragments. This
flaw is known as Fragnesia. A local attacker could use this to escalate
privileges, or possibly escape a container. (CVE-2026-43503)
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:
- SCSI subsystem;
- Thermal drivers;
- USB over IP driver;
- File systems infrastructure;
- Ext4 file system;
- Network file system (NFS) server daemon;
- SMB network file system;
- Tracing infrastructure;
- B.A.T.M.A.N. meshing protocol;
- Ceph Core library;
- DCCP (Datagram Congestion Control Protocol);
- IPv4 networking;
- IPv6 networking;
- Netfilter;
- RxRPC session sockets;
- X.25 network layer;
(CVE-2021-47117, CVE-2021-47202, CVE-2023-52646, CVE-2024-56643,
CVE-2026-23455, CVE-2026-31402, CVE-2026-31607, CVE-2026-31637,
CVE-2026-31659, CVE-2026-31685, CVE-2026-43011, CVE-2026-43037,
CVE-2026-43038, CVE-2026-43383, CVE-2026-43407, CVE-2026-43414,
CVE-2026-45988, CVE-2026-46119, CVE-2026-46243)
Fixed packages 3
| Release | Package | Fixed in |
|---|---|---|
| Ubuntu · Pro 16.04 LTS Pro:16.04:LTS | linux | 4.4.0-283.317 |
| Ubuntu · Pro 16.04 LTS Pro:16.04:LTS | linux-aws | 4.4.0-1194.209 |
| Ubuntu · Pro 16.04 LTS Pro:16.04:LTS | linux-kvm | 4.4.0-1157.168 |
Vulnerabilities 20
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Critical 9.8CVE-2026-31402 Public exploit
nfsd: fix heap overflow in NFSv4.0 LOCK replay cache
In the Linux kernel, the following vulnerability has been resolved: nfsd: fix heap overflow in NFSv4.0 LOCK replay cache The NFSv4.0 replay cache uses a fixed 112-byte inline buffer (rp_ibuf[NFSD4_REPLAY_ISIZE]) to store encoded operation responses. This size…
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Critical 9.8
usbip: validate number_of_packets in usbip_pack_ret_submit()
In the Linux kernel, the following vulnerability has been resolved: usbip: validate number_of_packets in usbip_pack_ret_submit() When a USB/IP client receives a RET_SUBMIT response, usbip_pack_ret_submit() unconditionally overwrites urb->number_of_packets fro…
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Critical 9.8
rxrpc: reject undecryptable rxkad response tickets
In the Linux kernel, the following vulnerability has been resolved: rxrpc: reject undecryptable rxkad response tickets rxkad_decrypt_ticket() decrypts the RXKAD response ticket and then parses the buffer as plaintext without checking whether crypto_skcipher_d…
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Critical 9.8
batman-adv: reject oversized global TT response buffers
In the Linux kernel, the following vulnerability has been resolved: batman-adv: reject oversized global TT response buffers batadv_tt_prepare_tvlv_global_data() builds the allocation length for a global TT response in 16-bit temporaries. When a remote origina…
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Critical 9.8
net/x25: Fix potential double free of skb
In the Linux kernel, the following vulnerability has been resolved: net/x25: Fix potential double free of skb When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at line 48 and returns 1 (error). This error propagates back through the call chai…
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Critical 9.8
ip6_tunnel: clear skb2->cb[] in ip4ip6_err()
In the Linux kernel, the following vulnerability has been resolved: ip6_tunnel: clear skb2->cb[] in ip4ip6_err() Oskar Kjos reported the following problem. ip4ip6_err() calls icmp_send() on a cloned skb whose cb[] was written by the IPv6 receive path as struc…
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Critical 9.8
ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach()
In the Linux kernel, the following vulnerability has been resolved: ipv6: icmp: clear skb2->cb[] in ip6_err_gen_icmpv6_unreach() Sashiko AI-review observed: In ip6_err_gen_icmpv6_unreach(), the skb is an outer IPv4 ICMP error packet where its cb contains an I…
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Critical 9.8
scsi: qla2xxx: Completely fix fcport double free
In the Linux kernel, the following vulnerability has been resolved: scsi: qla2xxx: Completely fix fcport double free In qla24xx_els_dcmd_iocb() sp->free is set to qla2x00_els_dcmd_sp_free(). When an error happens, this function is called by qla2x00_sp_release…
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Critical 9.8
rxrpc: Fix re-decryption of RESPONSE packets
In the Linux kernel, the following vulnerability has been resolved: rxrpc: Fix re-decryption of RESPONSE packets If a RESPONSE packet gets a temporary failure during processing, it may end up in a partially decrypted state - and then get requeued for a retry.…
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Critical 9.4
netfilter: ip6t_eui64: reject invalid MAC header for all packets
In the Linux kernel, the following vulnerability has been resolved: netfilter: ip6t_eui64: reject invalid MAC header for all packets `eui64_mt6()` derives a modified EUI-64 from the Ethernet source address and compares it with the low 64 bits of the IPv6 sour…
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Critical 9.4
net/tcp-md5: Fix MAC comparison to be constant-time
In the Linux kernel, the following vulnerability has been resolved: net/tcp-md5: Fix MAC comparison to be constant-time To prevent timing attacks, MACs need to be compared in constant time. Use the appropriate helper function for this.
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Critical 9.1
netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: check for zero length in DecodeQ931() In DecodeQ931(), the UserUserIE code path reads a 16-bit length from the packet, then decrements it by 1 to skip the protoc…
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Critical 9.1
libceph: Fix potential out-of-bounds access in ceph_handle_auth_reply()
In the Linux kernel, the following vulnerability has been resolved: libceph: Fix potential out-of-bounds access in ceph_handle_auth_reply() This patch fixes an out-of-bounds access in ceph_handle_auth_reply() that can be triggered by a message of type CEPH_MS…
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Critical 9.1
libceph: Fix slab-out-of-bounds access in auth message processing
In the Linux kernel, the following vulnerability has been resolved: libceph: Fix slab-out-of-bounds access in auth message processing If a (potentially corrupted) message of type CEPH_MSG_AUTH_REPLY contains a positive value in its result field, it is treated…
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High 8.8CVE-2026-43503 Public exploit
net: skbuff: propagate shared-frag marker through frag-transfer helpers
In the Linux kernel, the following vulnerability has been resolved: net: skbuff: propagate shared-frag marker through frag-transfer helpers Two frag-transfer helpers (__pskb_copy_fclone() and skb_shift()) fail to propagate the SKBFL_SHARED_FRAG bit in skb_shi…
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High 7.1CVE-2026-46243 Public exploit
smb: client: reject userspace cifs.spnego descriptions
In the Linux kernel, the following vulnerability has been resolved: smb: client: reject userspace cifs.spnego descriptions cifs.spnego key descriptions contain authority-bearing fields such as pid, uid, creduid, and upcall_target that cifs.upcall treats as ke…
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Low 3.3
dccp: Fix memory leak in dccp_feat_change_recv
In the Linux kernel, the following vulnerability has been resolved: dccp: Fix memory leak in dccp_feat_change_recv If dccp_feat_push_confirm() fails after new value for SP feature was accepted without reconciliation ('entry == NULL' branch), memory allocated …
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Unscored —
ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failed
In the Linux kernel, the following vulnerability has been resolved: ext4: fix bug on in ext4_es_cache_extent as ext4_split_extent_at failed We got follow bug_on when run fsstress with injecting IO fault: [130747.323114] kernel BUG at fs/ext4/extents_status.c:…
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Unscored —
thermal: Fix NULL pointer dereferences in of_thermal_ functions
In the Linux kernel, the following vulnerability has been resolved: thermal: Fix NULL pointer dereferences in of_thermal_ functions of_parse_thermal_zones() parses the thermal-zones node and registers a thermal_zone device for each subnode. However, if a ther…
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Unscored —
aio: fix mremap after fork null-deref
In the Linux kernel, the following vulnerability has been resolved: aio: fix mremap after fork null-deref Commit e4a0d3e720e7 ("aio: Make it possible to remap aio ring") introduced a null-deref if mremap is called on an old aio mapping after fork as mm->ioctx…
References
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report
https://ubuntu.com/security/CVE-2021-47117
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report
https://ubuntu.com/security/CVE-2021-47202
-
report
https://ubuntu.com/security/CVE-2023-52646
-
report
https://ubuntu.com/security/CVE-2024-56643
-
report
https://ubuntu.com/security/CVE-2026-23455
-
report
https://ubuntu.com/security/CVE-2026-31402
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report
https://ubuntu.com/security/CVE-2026-31607
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report
https://ubuntu.com/security/CVE-2026-31637
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report
https://ubuntu.com/security/CVE-2026-31659
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report
https://ubuntu.com/security/CVE-2026-31685
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report
https://ubuntu.com/security/CVE-2026-43011
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report
https://ubuntu.com/security/CVE-2026-43037
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report
https://ubuntu.com/security/CVE-2026-43038
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report
https://ubuntu.com/security/CVE-2026-43383
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report
https://ubuntu.com/security/CVE-2026-43407
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report
https://ubuntu.com/security/CVE-2026-43414
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report
https://ubuntu.com/security/CVE-2026-43503
-
report
https://ubuntu.com/security/CVE-2026-45988
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report
https://ubuntu.com/security/CVE-2026-46119
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report
https://ubuntu.com/security/CVE-2026-46243