Divide By Zero Affecting rtla package, versions *


Severity

Recommended
medium

Based on Red Hat Enterprise Linux security rating.

Threat Intelligence

EPSS
0.46% (39th percentile)

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  • Snyk IDSNYK-RHEL10-RTLA-19930400
  • published19 Sept 2026
  • disclosed11 Sept 2026

Introduced: 11 Sep 2026

NewCVE-2026-89550  (opens in a new tab)
CWE-369  (opens in a new tab)

How to fix?

There is no fixed version for RHEL:10 rtla.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rtla package and not the rtla package as distributed by RHEL. See How to fix? for RHEL:10 relevant fixed versions and status.

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

SUNRPC: svcauth_gss: enforce krb5 token minimum length

svcauth_gss_unwrap_priv() validates only an upper bound on the wire-supplied opaque length before handing the buffer to gss_unwrap():

if (len > xdr_stream_remaining(xdr))
        goto unwrap_failed;
offset = xdr_stream_pos(xdr);
...
maj_stat = gss_unwrap(ctx, offset, offset + len, buf);

The wire value len flows unchanged as the upper bound into the krb5 unwrap path, so a len in [0, 16] passes this check and is handed to gss_unwrap(). For a krb5 v2 context that lands in gss_krb5_unwrap_v2(), which reads the 16-byte RFC 4121 token header fields at ptr+4 and ptr+6 and then calls rotate_left() before any integrity check. With a sub-header length the header reads run past the token, and _rotate_left()'s shift %= buf->len path can divide by zero when buf->len has been driven to zero by the truncated token. A header-only token (len == 16) is equally invalid: with a non-zero RRC field and the opaque blob ending at the XDR buffer boundary, rotate_left() builds a zero-length subbuffer, reaching the same division.

Reject the token at the server entry point before it reaches the krb5 unwrap core. A valid sealed RFC 4121 token must contain the 16-byte header plus at least some encrypted payload.

Fix by adding a minimum-length check immediately after the existing upper-bound check:

if (len <= GSS_KRB5_TOK_HDR_LEN)
        goto unwrap_failed;

CVSS Base Scores

version 3.1