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CVE-2024-52811
No affected components available
The ngtcp2 project is an effort to implement IETF QUIC protocol in C. In affected versions acks are not validated before being written to the qlog leading to a buffer overflow. In ngtcp2_conn::conn_recv_pkt for an ACK, there was new logic that got added to skip conn_recv_ack if an ack has already been processed in the payload. However, this causes us to also skip ngtcp2_pkt_validate_ack. The ack which was skipped still got written to qlog. The bug occurs in ngtcp2_qlog::write_ack_frame. It is now possible to reach this code with an invalid ack, suppose largest_ack=0 and first_ack_range=15. Subtracting largest_ack - first_ack_range will lead to an integer underflow which is 20 chars long. However, the ngtcp2 qlog code assumes the number written is a signed integer and only accounts for 19 characters of overhead (see NGTCP2_QLOG_ACK_FRAME_RANGE_OVERHEAD). Therefore, we overwrite the buffer causing a heap overflow. This is high priority and could potentially impact many users if they enable qlog. qlog is disabled by default. Due to its overhead, it is most likely used for debugging purpose, but the actual use is unknown. ngtcp2 v1.9.1 fixes the bug and users are advised to upgrade. Users unable to upgrade should not turn on qlog.
The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the integrity of the data. There is a high impact on the availability of the system.
Exploitation activity has been observed. Apply available patches or mitigations urgently.
The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.
We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.
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