Описание
NLnet Labs Unbound 1.22.0 up to and including 1.26.1, has a use-after-free vulnerability when compiled for DNS-over-QUIC support with '--with-libngtcp2'. Each DoQ stream owns an output buffer that holds the DNS response. ngtcp2's retransmission buffer keeps a shallow pointer into the output buffer for as long as a STREAM frame may be resent. On a client RESET_STREAM, the output buffer is freed but ngtcp2 still holds the matching retransmission entries. The next PTO timeout makes ngtcp2 re-encode the STREAM frame and copy from the freed buffer. A malicious actor that can query Unbound over DoQ and that withholds ACKs, sends RESET_STREAM, and waits for PTO, reaches this use-after-free with no privilege. This leads to retransmissions against freed memory and eventually an abnormal server exit under a 20-query spray.
| Релиз | Статус | Примечание |
|---|---|---|
| devel | needs-triage | |
| esm-infra-legacy/trusty | needs-triage | |
| esm-infra-legacy/xenial | needs-triage | |
| esm-infra/bionic | needs-triage | |
| esm-infra/focal | needs-triage | |
| jammy | needs-triage | |
| noble | needs-triage | |
| resolute | needs-triage | |
| upstream | released | 1.26.1-1 |
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6.5 Medium
CVSS3
Связанные уязвимости
A flaw was found in Unbound. This vulnerability occurs in the DNS-over-QUIC (DoQ) stream output buffer when a client sends a RESET_STREAM, causing the output buffer to be freed while retransmission entries still point to it. A remote attacker, by querying Unbound over DoQ, withholding acknowledgments, and sending a RESET_STREAM, can trigger this flaw. This leads to retransmissions against freed memory, ultimately resulting in a denial of service due to an abnormal server exit.
NLnet Labs Unbound 1.22.0 up to and including 1.26.1, has a use-after-free vulnerability when compiled for DNS-over-QUIC support with '--with-libngtcp2'. Each DoQ stream owns an output buffer that holds the DNS response. ngtcp2's retransmission buffer keeps a shallow pointer into the output buffer for as long as a STREAM frame may be resent. On a client RESET_STREAM, the output buffer is freed but ngtcp2 still holds the matching retransmission entries. The next PTO timeout makes ngtcp2 re-encode the STREAM frame and copy from the freed buffer. A malicious actor that can query Unbound over DoQ and that withholds ACKs, sends RESET_STREAM, and waits for PTO, reaches this use-after-free with no privilege. This leads to retransmissions against freed memory and eventually an abnormal server exit under a 20-query spray.
Use-after-free in DoQ stream output buffer on reset re-transmission
NLnet Labs Unbound 1.22.0 up to and including 1.26.1, has a use-after-free vulnerability when compiled for DNS-over-QUIC support with '--with-libngtcp2'. Each DoQ stream owns an output buffer that holds the DNS response. ngtcp2's retransmission buffer keeps a shallow pointer into the output buffer for as long as a STREAM frame may be resent. On a client RESET_STREAM, the output buffer is freed but ngtcp2 still holds the matching retransmission entries. The next PTO timeout makes ngtcp2 re-encode the STREAM frame and copy from the freed buffer. A malicious actor that can query Unbound over DoQ and that withholds ACKs, sends RESET_STREAM, and waits for PTO, reaches this use-after-free with no privilege. This leads to retransmissions against freed memory and eventually an abnormal server exit under a 20-query spray.
6.5 Medium
CVSS3