user8291: As title above, what are a few of the worst blunders ever committed in a World Chess Championship Match?

user4362: Game six in the second Carlsen-Anand match comes to mind. 
After 26.Kd2 black can simply take on e5 and after 26...Nxe5 27.Rxg8 he has the intermediate check 27...Nxc4+. Black just remains at least one pawn up. 
So, 26.Kd2 is one of the worst blunders in the history of the world championship. But of course 26...a4 forgoing this relatively simple tactical strike is also one of the worst blunders.
[Event "Carlsen - Anand World Championship"]
[Site "Sochi RUS"]
[Date "2014.11.15"]
[EventDate "2014.11.07"]
[Round "6"]
[Result "1-0"]
[White "Magnus Carlsen"]
[Black "Viswanathan Anand"]
[ECO "B41"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "75"]

[fen ""]

1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 a6 5.c4 Nf6 6.Nc3 Bb4 
7.Qd3 Nc6 8.Nxc6 dxc6 9.Qxd8+ Kxd8 10.e5 Nd7 11.Bf4 Bxc3+ 
12.bxc3 Kc7 13.h4 b6 14.h5 h6 15.O-O-O Bb7 16.Rd3 c5 17.Rg3 Rag8
18.Bd3 Nf8 19.Be3 g6 20.hxg6 Nxg6 21.Rh5 Bc6 22.Bc2 Kb7 
23.Rg4 a5 24.Bd1 Rd8 25.Bc2 Rdg8 26.Kd2 a4 27.Ke2 a3 28.f3 Rd8 
29.Ke1 Rd7 30.Bc1 Ra8 31.Ke2 Ba4 32.Be4+ Bc6 33.Bxg6 fxg6 
34.Rxg6 Ba4 35.Rxe6 Rd1 36.Bxa3 Ra1 37.Ke3 Bc2 38.Re7+ 1-0


user8860: As it happens Chessbase ran a story earlier this week featuring
"eight egregious elite errors"
from past World Championship matches.  They are Chigorin-Steinitz (noted by SmallChess), Bronstein-Botvinnik, Spassky-Fischer (blunders from two games, Fischer's famous Bxh2? and one from Spassky), Korchnoi-Karpov (Korchnoi allowed mate in 3 in a RRPPP/RNN endgame), Kasparov-Karpov, Kramnik-Leko, and the mutual Carlsen-Anand blunder in the answer from BlindKungFuMaster.

user825: By far, the biggest blunder in all world championship is absolutely 32.Bb4?? played by Chigorin in the 1892 match. He threw away the win and the match, landed himself to mate in 2.

https://en.wikipedia.org/wiki/World_Chess_Championship_1892
A piece up, Chigorin should have won after 32. Rxb7 (32...Rxd5? 33. Nf4 forks the black rooks).[1] Instead the game and match ended suddenly when Chigorin blundered with 32. Bb4?? Rxh2+ White resigns, as Black will mate on the next move.[1][3]


8291: <p>As title above, what are a few of the worst blunders ever committed in a World Chess Championship Match?</p>
 4362: <p>Game six in the second Carlsen-Anand match comes to mind. </p>

<p>After 26.Kd2 black can simply take on e5 and after 26...Nxe5 27.Rxg8 he has the intermediate check 27...Nxc4+. Black just remains at least one pawn up. </p>

<p>So, 26.Kd2 is one of the worst blunders in the history of the world championship. But of course 26...a4 forgoing this relatively simple tactical strike is also one of the worst blunders.</p>

<pre><code>[Event "Carlsen - Anand World Championship"]
[Site "Sochi RUS"]
[Date "2014.11.15"]
[EventDate "2014.11.07"]
[Round "6"]
[Result "1-0"]
[White "Magnus Carlsen"]
[Black "Viswanathan Anand"]
[ECO "B41"]
[WhiteElo "?"]
[BlackElo "?"]
[PlyCount "75"]

[fen ""]

1.e4 c5 2.Nf3 e6 3.d4 cxd4 4.Nxd4 a6 5.c4 Nf6 6.Nc3 Bb4 
7.Qd3 Nc6 8.Nxc6 dxc6 9.Qxd8+ Kxd8 10.e5 Nd7 11.Bf4 Bxc3+ 
12.bxc3 Kc7 13.h4 b6 14.h5 h6 15.O-O-O Bb7 16.Rd3 c5 17.Rg3 Rag8
18.Bd3 Nf8 19.Be3 g6 20.hxg6 Nxg6 21.Rh5 Bc6 22.Bc2 Kb7 
23.Rg4 a5 24.Bd1 Rd8 25.Bc2 Rdg8 26.Kd2 a4 27.Ke2 a3 28.f3 Rd8 
29.Ke1 Rd7 30.Bc1 Ra8 31.Ke2 Ba4 32.Be4+ Bc6 33.Bxg6 fxg6 
34.Rxg6 Ba4 35.Rxe6 Rd1 36.Bxa3 Ra1 37.Ke3 Bc2 38.Re7+ 1-0
</code></pre>
 8860: <p>As it happens <a href="http://chessbase.com" rel="noreferrer">Chessbase</a> ran a story earlier this week featuring
"<a href="https://en.chessbase.com/post/speelman-agony-87" rel="noreferrer">eight egregious elite errors</a>"
from past World Championship matches.  They are Chigorin-Steinitz (noted by <strong>SmallChess</strong>), Bronstein-Botvinnik, Spassky-Fischer (blunders from two games, Fischer's famous Bxh2? and one from Spassky), Korchnoi-Karpov (Korchnoi allowed mate in 3 in a RRPPP/RNN endgame), Kasparov-Karpov, Kramnik-Leko, and the mutual Carlsen-Anand blunder in the answer from <strong>BlindKungFuMaster</strong>.</p>
 825: <p>By far, the biggest blunder in all world championship is absolutely 32.Bb4?? played by Chigorin in the 1892 match. He threw away the win and the match, landed himself to mate in 2.</p>
<blockquote>
<p><a href="https://en.wikipedia.org/wiki/World_Chess_Championship_1892" rel="noreferrer">https://en.wikipedia.org/wiki/World_Chess_Championship_1892</a></p>
<p>A piece up, Chigorin should have won after 32. Rxb7 (32...Rxd5? 33. Nf4 forks the black rooks).[1] Instead the game and match ended suddenly when Chigorin blundered with 32. Bb4?? Rxh2+ White resigns, as Black will mate on the next move.[1][3]</p>
</blockquote>
